Author: "Satzinger, Kevin" - Searchworks@Jio Institute Digital Library Search Results

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1. Demonstrating dynamic surface codes

Author: Eickbusch, Alec, McEwen, Matt, Sivak, Volodymyr, Bourassa, Alexandre, Atalaya, Juan, Claes, Jahan, Kafri, Dvir, Gidney, Craig, Warren, Christopher W., Gross, Jonathan, Opremcak, Alex, Miao, Nicholas Zobrist Kevin C., Roberts, Gabrielle, Satzinger, Kevin J., Bengtsson, Andreas, Neeley, Matthew, Livingston, William P., Greene, Alex, Rajeev, Acharya, Beni, Laleh Aghababaie, Aigeldinger, Georg, Alcaraz, Ross, Andersen, Trond I., Ansmann, Markus, Frank, Arute, Arya, Kunal, Asfaw, Abraham, Babbush, Ryan, Ballard, Brian, Bardin, Joseph C., Bilmes, Alexander, Jenna, Bovaird, Bowers, Dylan, Brill, Leon, Broughton, Michael, Browne, David A., Buchea, Brett, Buckley, Bob B., Tim, Burger, Burkett, Brian, Bushnell, Nicholas, Cabrera, Anthony, Campero, Juan, Chang, Hung-Shen, Chiaro, Ben, Chih, Liang-Ying, Cleland, Agnetta Y., Cogan, Josh, Collins, Roberto, Conner, Paul, Courtney, William, Alexander, Crook, L., Curtin, Ben, Das, Sayan, Barba, Alexander Del Toro, Demura, Sean, De Lorenzo, Laura, Di Paolo, Agustin, Donohoe, Paul, Drozdov, Ilya K., Dunsworth, Andrew, Elbag, Aviv Moshe, Elzouka, Mahmoud, Erickson, Catherine, Ferreira, Vinicius S., Burgos, Leslie Flores, Forati, Ebrahim, Fowler, Austin G., Foxen, Brooks, Ganjam, Suhas, Gonzalo, Garcia, Gasca, Robert, Genois, Élie, Giang, William, Gilboa, Dar, Gosula, Raja, Dau, Alejandro Grajales, Dietrich, Graumann, Ha, Tan, Habegger, Steve, Hansen, Monica, Harrigan, Matthew P., Harrington, Sean D., Heslin, Stephen, Heu, Paula, Higgott, Oscar, Hiltermann, Reno, Hilton, Jeremy, Huang, Hsin-Yuan, Huff, Ashley, Huggins, William J., Jeffrey, Evan, Jiang, Zhang, Jin, Xiaoxuan, Jones, Cody, Joshi, Chaitali, Juhas, Pavol, Kabel, Andreas, Kang, Hui, Amir, Karamlou, H., Kechedzhi, Kostyantyn, Khaire, Trupti, Khattar, Tanuj, Khezri, Mostafa, Kim, Seon, Kobrin, Bryce, Korotkov, Alexander N., Kostritsa, Fedor, Kreikebaum, John Mark, Kurilovich, Vladislav D., Landhuis, David, Tiano, Lange-Dei, Langley, Brandon W., Lau, Kim-Ming, Ledford, Justin, Lee, Kenny, Lester, Brian J., Guevel, Loïck Le, Wing, Li, Yan, Lill, Alexander T., Locharla, Aditya, Lucero, Erik, Lundahl, Daniel, Lunt, Aaron, Madhuk, Sid, Maloney, Ashley, Mandrà, Salvatore, Martin, Leigh S., Martin, Orion, Maxfield, Cameron, McClean, Jarrod R., Meeks, Seneca, Anthony, Megrant, Molavi, Reza, Molina, Sebastian, Montazeri, Shirin, Movassagh, Ramis, Newman, Michael, Nguyen, Anthony, Nguyen, Murray, Ni, Chia-Hung, Oas, Logan, Orosco, Raymond, Ottosson, Kristoffer, Pizzuto, Alex, Potter, Rebecca, Pritchard, Orion, Quintana, Chris, Ramachandran, Ganesh, Reagor, Matthew J., Rhodes, David M., Rosenberg, Eliott, Rossi, Elizabeth, Sankaragomathi, Kannan, Schurkus, Henry F., Shearn, Michael J., Shorter, Aaron, Shutty, Noah, Shvarts, Vladimir, Small, Spencer, Smith, W. Clarke, Springer, Sofia, Sterling, George, Suchard, Jordan, Szasz, Aaron, Sztein, Alex, Thor, Douglas, Tomita, Eifu, Torres, Alfredo, Torunbalci, M. Mert, Vaishnav, Abeer, Vargas, Justin, Sergey, Vdovichev, Vidal, Guifre, Heidweiller, Catherine Vollgraff, Waltman, Steven, Waltz, Jonathan, Wang, Shannon X., Ware, Brayden, Weidel, Travis, White, Theodore, Wong, Kristi, Woo, Bryan W. K., Woodson, Maddy, Xing, Cheng, Yao, Z. Jamie, Yeh, Ping, Ying, Bicheng, Yoo, Juhwan, Yosri, Noureldin, Young, Grayson, Zalcman, Adam, Yaxing, Zhang, Zhu, Ningfeng, Boixo, Sergio, Kelly, Julian, Smelyanskiy, Vadim, Neven, Hartmut, Bacon, Dave, Chen, Zijun, Klimov, Paul V., Roushan, Pedram, Neill, Charles, Chen, Yu, and Morvan, Alexis
Subjects: Quantum Physics
Abstract: A remarkable characteristic of quantum computing is the potential for reliable computation despite faulty qubits. This can be achieved through quantum error correction, which is typically implemented by repeatedly applying static syndrome checks, permitting correction of logical information. Recently, the development of time-dynamic approaches to error correction has uncovered new codes and new code implementations. In this work, we experimentally demonstrate three time-dynamic implementations of the surface code, each offering a unique solution to hardware design challenges and introducing flexibility in surface code realization. First, we embed the surface code on a hexagonal lattice, reducing the necessary couplings per qubit from four to three. Second, we walk a surface code, swapping the role of data and measure qubits each round, achieving error correction with built-in removal of accumulated non-computational errors. Finally, we realize the surface code using iSWAP gates instead of the traditional CNOT, extending the set of viable gates for error correction without additional overhead. We measure the error suppression factor when scaling from distance-3 to distance-5 codes of $\Lambda_{35,\text{hex}} = 2.15(2)$, $\Lambda_{35,\text{walk}} = 1.69(6)$, and $\Lambda_{35,\text{iSWAP}} = 1.56(2)$, achieving state-of-the-art error suppression for each. With detailed error budgeting, we explore their performance trade-offs and implications for hardware design. This work demonstrates that dynamic circuit approaches satisfy the demands for fault-tolerance and opens new alternative avenues for scalable hardware design., Comment: 11 pages, 5 figures, Supplementary Information
Published: 2024

2. Scaling and logic in the color code on a superconducting quantum processor

Author: Lacroix, Nathan, Bourassa, Alexandre, Heras, Francisco J. H., Zhang, Lei M., Bausch, Johannes, Senior, Andrew W., Edlich, Thomas, Shutty, Noah, Sivak, Volodymyr, Bengtsson, Andreas, McEwen, Matt, Higgott, Oscar, Kafri, Dvir, Claes, Jahan, Morvan, Alexis, Chen, Zijun, Zalcman, Adam, Madhuk, Sid, Acharya, Rajeev, Beni, Laleh Aghababaie, Aigeldinger, Georg, Alcaraz, Ross, Andersen, Trond I., Ansmann, Markus, Arute, Frank, Arya, Kunal, Asfaw, Abraham, Atalaya, Juan, Babbush, Ryan, Ballard, Brian, Bardin, Joseph C., Bilmes, Alexander, Blackwell, Sam, Bovaird, Jenna, Bowers, Dylan, Brill, Leon, Broughton, Michael, Browne, David A., Buchea, Brett, Buckley, Bob B., Burger, Tim, Burkett, Brian, Bushnell, Nicholas, Cabrera, Anthony, Campero, Juan, Chang, Hung-Shen, Chiaro, Ben, Chih, Liang-Ying, Cleland, Agnetta Y., Cogan, Josh, Collins, Roberto, Conner, Paul, Courtney, William, Crook, Alexander L., Curtin, Ben, Das, Sayan, Demura, Sean, De Lorenzo, Laura, Di Paolo, Agustin, Donohoe, Paul, Drozdov, Ilya, Dunsworth, Andrew, Eickbusch, Alec, Elbag, Aviv Moshe, Elzouka, Mahmoud, Erickson, Catherine, Ferreira, Vinicius S., Burgos, Leslie Flores, Forati, Ebrahim, Fowler, Austin G., Foxen, Brooks, Ganjam, Suhas, Garcia, Gonzalo, Gasca, Robert, Genois, Élie, Giang, William, Gilboa, Dar, Gosula, Raja, Dau, Alejandro Grajales, Graumann, Dietrich, Greene, Alex, Gross, Jonathan A., Ha, Tan, Habegger, Steve, Hansen, Monica, Harrigan, Matthew P., Harrington, Sean D., Heslin, Stephen, Heu, Paula, Hiltermann, Reno, Hilton, Jeremy, Hong, Sabrina, Huang, Hsin-Yuan, Huff, Ashley, Huggins, William J., Jeffrey, Evan, Jiang, Zhang, Jin, Xiaoxuan, Joshi, Chaitali, Juhas, Pavol, Kabel, Andreas, Kang, Hui, Karamlou, Amir H., Kechedzhi, Kostyantyn, Khaire, Trupti, Khattar, Tanuj, Khezri, Mostafa, Kim, Seon, Klimov, Paul V., Kobrin, Bryce, Korotkov, Alexander N., Kostritsa, Fedor, Kreikebaum, John Mark, Kurilovich, Vladislav D., Landhuis, David, Lange-Dei, Tiano, Langley, Brandon W., Laptev, Pavel, Lau, Kim-Ming, Ledford, Justin, Lee, Kenny, Lester, Brian J., Guevel, Loïck Le, Li, Wing Yan, Li, Yin, Lill, Alexander T., Livingston, William P., Locharla, Aditya, Lucero, Erik, Lundahl, Daniel, Lunt, Aaron, Maloney, Ashley, Mandrà, Salvatore, Martin, Leigh S., Martin, Orion, Maxfield, Cameron, McClean, Jarrod R., Meeks, Seneca, Megrant, Anthony, Miao, Kevin C., Molavi, Reza, Molina, Sebastian, Montazeri, Shirin, Movassagh, Ramis, Neill, Charles, Newman, Michael, Nguyen, Anthony, Nguyen, Murray, Ni, Chia-Hung, Niu, Murphy Y., Oas, Logan, Oliver, William D., Orosco, Raymond, Ottosson, Kristoffer, Pizzuto, Alex, Potter, Rebecca, Pritchard, Orion, Quintana, Chris, Ramachandran, Ganesh, Reagor, Matthew J., Resnick, Rachel, Rhodes, David M., Roberts, Gabrielle, Rosenberg, Eliott, Rosenfeld, Emma, Rossi, Elizabeth, Roushan, Pedram, Sankaragomathi, Kannan, Schurkus, Henry F., Shearn, Michael J., Shorter, Aaron, Shvarts, Vladimir, Small, Spencer, Smith, W. Clarke, Springer, Sofia, Sterling, George, Suchard, Jordan, Szasz, Aaron, Sztein, Alex, Thor, Douglas, Tomita, Eifu, Torres, Alfredo, Torunbalci, M. Mert, Vaishnav, Abeer, Vargas, Justin, Vdovichev, Sergey, Vidal, Guifre, Heidweiller, Catherine Vollgraff, Waltman, Steven, Waltz, Jonathan, Wang, Shannon X., Ware, Brayden, Weidel, Travis, White, Theodore, Wong, Kristi, Woo, Bryan W. K., Woodson, Maddy, Xing, Cheng, Yao, Z. Jamie, Yeh, Ping, Ying, Bicheng, Yoo, Juhwan, Yosri, Noureldin, Young, Grayson, Zhang, Yaxing, Zhu, Ningfeng, Zobrist, Nicholas, Neven, Hartmut, Kohli, Pushmeet, Davies, Alex, Boixo, Sergio, Kelly, Julian, Jones, Cody, Gidney, Craig, and Satzinger, Kevin J.
Subjects: Quantum Physics
Abstract: Quantum error correction is essential for bridging the gap between the error rates of physical devices and the extremely low logical error rates required for quantum algorithms. Recent error-correction demonstrations on superconducting processors have focused primarily on the surface code, which offers a high error threshold but poses limitations for logical operations. In contrast, the color code enables much more efficient logic, although it requires more complex stabilizer measurements and decoding techniques. Measuring these stabilizers in planar architectures such as superconducting qubits is challenging, and so far, realizations of color codes have not addressed performance scaling with code size on any platform. Here, we present a comprehensive demonstration of the color code on a superconducting processor, achieving logical error suppression and performing logical operations. Scaling the code distance from three to five suppresses logical errors by a factor of $\Lambda_{3/5}$ = 1.56(4). Simulations indicate this performance is below the threshold of the color code, and furthermore that the color code may be more efficient than the surface code with modest device improvements. Using logical randomized benchmarking, we find that transversal Clifford gates add an error of only 0.0027(3), which is substantially less than the error of an idling error correction cycle. We inject magic states, a key resource for universal computation, achieving fidelities exceeding 99% with post-selection (retaining about 75% of the data). Finally, we successfully teleport logical states between distance-three color codes using lattice surgery, with teleported state fidelities between 86.5(1)% and 90.7(1)%. This work establishes the color code as a compelling research direction to realize fault-tolerant quantum computation on superconducting processors in the near future.
Published: 2024

3. Observation of disorder-free localization and efficient disorder averaging on a quantum processor

Author: Gyawali, Gaurav, Cochran, Tyler, Lensky, Yuri, Rosenberg, Eliott, Karamlou, Amir H., Kechedzhi, Kostyantyn, Berndtsson, Julia, Westerhout, Tom, Asfaw, Abraham, Abanin, Dmitry, Acharya, Rajeev, Beni, Laleh Aghababaie, Andersen, Trond I., Ansmann, Markus, Arute, Frank, Arya, Kunal, Astrakhantsev, Nikita, Atalaya, Juan, Babbush, Ryan, Ballard, Brian, Bardin, Joseph C., Bengtsson, Andreas, Bilmes, Alexander, Bortoli, Gina, Bourassa, Alexandre, Bovaird, Jenna, Brill, Leon, Broughton, Michael, Browne, David A., Buchea, Brett, Buckley, Bob B., Buell, David A., Burger, Tim, Burkett, Brian, Bushnell, Nicholas, Cabrera, Anthony, Campero, Juan, Chang, Hung-Shen, Chen, Zijun, Chiaro, Ben, Claes, Jahan, Cleland, Agnetta Y., Cogan, Josh, Collins, Roberto, Conner, Paul, Courtney, William, Crook, Alexander L., Das, Sayan, Debroy, Dripto M., De Lorenzo, Laura, Barba, Alexander Del Toro, Demura, Sean, Di Paolo, Agustin, Donohoe, Paul, Drozdov, Ilya, Dunsworth, Andrew, Earle, Clint, Eickbusch, Alec, Elbag, Aviv Moshe, Elzouka, Mahmoud, Erickson, Catherine, Faoro, Lara, Fatemi, Reza, Ferreira, Vinicius S., Burgos, Leslie Flores, Forati, Ebrahim, Fowler, Austin G., Foxen, Brooks, Ganjam, Suhas, Gasca, Robert, Giang, William, Gidney, Craig, Gilboa, Dar, Gosula, Raja, Dau, Alejandro Grajales, Graumann, Dietrich, Greene, Alex, Gross, Jonathan A., Habegger, Steve, Hamilton, Michael C., Hansen, Monica, Harrigan, Matthew P., Harrington, Sean D., Heslin, Stephen, Heu, Paula, Hill, Gordon, Hilton, Jeremy, Hoffmann, Markus R., Huang, Hsin-Yuan, Huff, Ashley, Huggins, William J., Ioffe, Lev B., Isakov, Sergei V., Jeffrey, Evan, Jiang, Zhang, Jones, Cody, Jordan, Stephen, Joshi, Chaitali, Juhas, Pavol, Kafri, Dvir, Kang, Hui, Khaire, Trupti, Khattar, Tanuj, Khezri, Mostafa, Kieferová, Mária, Kim, Seon, Klimov, Paul V., Klots, Andrey R., Kobrin, Bryce, Korotkov, Alexander N., Kostritsa, Fedor, Kreikebaum, John Mark, Kurilovich, Vladislav D., Landhuis, David, Lange-Dei, Tiano, Langley, Brandon W., Laptev, Pavel, Lau, Kim-Ming, Guevel, Loïck Le, Ledford, Justin, Lee, Joonho, Lee, Kenny, Lester, Brian J., Li, Wing Yan, Lill, Alexander T., Liu, Wayne, Livingston, William P., Locharla, Aditya, Lundahl, Daniel, Lunt, Aaron, Madhuk, Sid, Maloney, Ashley, Mandrà, Salvatore, Martin, Leigh S., Martin, Steven, Martin, Orion, Maxfield, Cameron, McClean, Jarrod R., McEwen, Matt, Meeks, Seneca, Megrant, Anthony, Mi, Xiao, Miao, Kevin C., Mieszala, Amanda, Molina, Sebastian, Montazeri, Shirin, Morvan, Alexis, Movassagh, Ramis, Neill, Charles, Nersisyan, Ani, Newman, Michael, Nguyen, Anthony, Nguyen, Murray, Ni, Chia-Hung, Niu, Murphy Yuezhen, Oliver, William D., Ottosson, Kristoffer, Pizzuto, Alex, Potter, Rebecca, Pritchard, Orion, Pryadko, Leonid P., Quintana, Chris, Reagor, Matthew J., Rhodes, David M., Roberts, Gabrielle, Rocque, Charles, Rubin, Nicholas C., Saei, Negar, Sankaragomathi, Kannan, Satzinger, Kevin J., Schurkus, Henry F., Schuster, Christopher, Shearn, Michael J., Shorter, Aaron, Shutty, Noah, Shvarts, Vladimir, Sivak, Volodymyr, Skruzny, Jindra, Small, Spencer, Smith, W. Clarke, Springer, Sofia, Sterling, George, Suchard, Jordan, Szalay, Marco, Szasz, Aaron, Sztein, Alex, Thor, Douglas, Torunbalci, M. Mert, Vaishnav, Abeer, Vdovichev, Sergey, Vidal, Guifré, Heidweiller, Catherine Vollgraff, Waltman, Steven, Wang, Shannon X., White, Theodore, Wong, Kristi, Woo, Bryan W. K., Xing, Cheng, Yao, Z. Jamie, Yeh, Ping, Ying, Bicheng, Yoo, Juhwan, Yosri, Noureldin, Young, Grayson, Zalcman, Adam, Zhang, Yaxing, Zhu, Ningfeng, Zobrist, Nicholas, Boixo, Sergio, Kelly, Julian, Lucero, Erik, Chen, Yu, Smelyanskiy, Vadim, Neven, Hartmut, Kovrizhin, Dmitry, Knolle, Johannes, Halimeh, Jad C., Aleiner, Igor, Moessner, Roderich, and Roushan, Pedram
Subjects: Quantum Physics, Condensed Matter - Disordered Systems and Neural Networks, Condensed Matter - Strongly Correlated Electrons, High Energy Physics - Lattice
Abstract: One of the most challenging problems in the computational study of localization in quantum manybody systems is to capture the effects of rare events, which requires sampling over exponentially many disorder realizations. We implement an efficient procedure on a quantum processor, leveraging quantum parallelism, to efficiently sample over all disorder realizations. We observe localization without disorder in quantum many-body dynamics in one and two dimensions: perturbations do not diffuse even though both the generator of evolution and the initial states are fully translationally invariant. The disorder strength as well as its density can be readily tuned using the initial state. Furthermore, we demonstrate the versatility of our platform by measuring Renyi entropies. Our method could also be extended to higher moments of the physical observables and disorder learning.
Published: 2024

4. Visualizing Dynamics of Charges and Strings in (2+1)D Lattice Gauge Theories

Author: Cochran, Tyler A., Jobst, Bernhard, Rosenberg, Eliott, Lensky, Yuri D., Gyawali, Gaurav, Eassa, Norhan, Will, Melissa, Abanin, Dmitry, Acharya, Rajeev, Beni, Laleh Aghababaie, Andersen, Trond I., Ansmann, Markus, Arute, Frank, Arya, Kunal, Asfaw, Abraham, Atalaya, Juan, Babbush, Ryan, Ballard, Brian, Bardin, Joseph C., Bengtsson, Andreas, Bilmes, Alexander, Bourassa, Alexandre, Bovaird, Jenna, Broughton, Michael, Browne, David A., Buchea, Brett, Buckley, Bob B., Burger, Tim, Burkett, Brian, Bushnell, Nicholas, Cabrera, Anthony, Campero, Juan, Chang, Hung-Shen, Chen, Zijun, Chiaro, Ben, Claes, Jahan, Cleland, Agnetta Y., Cogan, Josh, Collins, Roberto, Conner, Paul, Courtney, William, Crook, Alexander L., Curtin, Ben, Das, Sayan, Demura, Sean, De Lorenzo, Laura, Di Paolo, Agustin, Donohoe, Paul, Drozdov, Ilya, Dunsworth, Andrew, Eickbusch, Alec, Elbag, Aviv Moshe, Elzouka, Mahmoud, Erickson, Catherine, Ferreira, Vinicius S., Burgos, Leslie Flores, Forati, Ebrahim, Fowler, Austin G., Foxen, Brooks, Ganjam, Suhas, Gasca, Robert, Genois, Élie, Giang, William, Gilboa, Dar, Gosula, Raja, Dau, Alejandro Grajales, Graumann, Dietrich, Greene, Alex, Gross, Jonathan A., Habegger, Steve, Hansen, Monica, Harrigan, Matthew P., Harrington, Sean D., Heu, Paula, Higgott, Oscar, Hilton, Jeremy, Huang, Hsin-Yuan, Huff, Ashley, Huggins, William J., Jeffrey, Evan, Jiang, Zhang, Jones, Cody, Joshi, Chaitali, Juhas, Pavol, Kafri, Dvir, Kang, Hui, Karamlou, Amir H., Kechedzhi, Kostyantyn, Khaire, Trupti, Khattar, Tanuj, Khezri, Mostafa, Kim, Seon, Klimov, Paul V., Kobrin, Bryce, Korotkov, Alexander N., Kostritsa, Fedor, Kreikebaum, John Mark, Kurilovich, Vladislav D., Landhuis, David, Lange-Dei, Tiano, Langley, Brandon W., Lau, Kim-Ming, Ledford, Justin, Lee, Kenny, Lester, Brian J., Guevel, Loïck Le, Li, Wing Yan, Lill, Alexander T., Livingston, William P., Locharla, Aditya, Lundahl, Daniel, Lunt, Aaron, Madhuk, Sid, Maloney, Ashley, Mandrà, Salvatore, Martin, Leigh S., Martin, Orion, Maxfield, Cameron, McClean, Jarrod R., McEwen, Matt, Meeks, Seneca, Megrant, Anthony, Miao, Kevin C., Molavi, Reza, Molina, Sebastian, Montazeri, Shirin, Movassagh, Ramis, Neill, Charles, Newman, Michael, Nguyen, Anthony, Nguyen, Murray, Ni, Chia-Hung, Niu, Murphy Yuezhen, Oliver, William D., Ottosson, Kristoffer, Pizzuto, Alex, Potter, Rebecca, Pritchard, Orion, Quintana, Chris, Ramachandran, Ganesh, Reagor, Matthew J., Rhodes, David M., Roberts, Gabrielle, Sankaragomathi, Kannan, Satzinger, Kevin J., Schurkus, Henry F., Shearn, Michael J., Shorter, Aaron, Shutty, Noah, Shvarts, Vladimir, Sivak, Volodymyr, Small, Spencer, Smith, W. Clarke, Springer, Sofia, Sterling, George, Suchard, Jordan, Szasz, Aaron, Sztein, Alex, Thor, Douglas, Torunbalci, M. Mert, Vaishnav, Abeer, Vargas, Justin, Vdovichev, Sergey, Vidal, Guifre, Heidweiller, Catherine Vollgraff, Waltman, Steven, Wang, Shannon X., Ware, Brayden, White, Theodore, Wong, Kristi, Woo, Bryan W. K., Xing, Cheng, Yao, Z. Jamie, Yeh, Ping, Ying, Bicheng, Yoo, Juhwan, Yosri, Noureldin, Young, Grayson, Zalcman, Adam, Zhang, Yaxing, Zhu, Ningfeng, Zobris, Nicholas, Boixo, Sergio, Kelly, Julian, Lucero, Erik, Chen, Yu, Smelyanskiy, Vadim, Neven, Hartmut, Gammon-Smith, Adam, Pollmann, Frank, Knap, Michael, and Roushan, Pedram
Subjects: Quantum Physics, Condensed Matter - Strongly Correlated Electrons, High Energy Physics - Lattice
Abstract: Lattice gauge theories (LGTs) can be employed to understand a wide range of phenomena, from elementary particle scattering in high-energy physics to effective descriptions of many-body interactions in materials. Studying dynamical properties of emergent phases can be challenging as it requires solving many-body problems that are generally beyond perturbative limits. We investigate the dynamics of local excitations in a $\mathbb{Z}_2$ LGT using a two-dimensional lattice of superconducting qubits. We first construct a simple variational circuit which prepares low-energy states that have a large overlap with the ground state; then we create particles with local gates and simulate their quantum dynamics via a discretized time evolution. As the effective magnetic field is increased, our measurements show signatures of transitioning from deconfined to confined dynamics. For confined excitations, the magnetic field induces a tension in the string connecting them. Our method allows us to experimentally image string dynamics in a (2+1)D LGT from which we uncover two distinct regimes inside the confining phase: for weak confinement the string fluctuates strongly in the transverse direction, while for strong confinement transverse fluctuations are effectively frozen. In addition, we demonstrate a resonance condition at which dynamical string breaking is facilitated. Our LGT implementation on a quantum processor presents a novel set of techniques for investigating emergent particle and string dynamics.
Published: 2024

5. Quantum error correction below the surface code threshold

Author: Acharya, Rajeev, Aghababaie-Beni, Laleh, Aleiner, Igor, Andersen, Trond I., Ansmann, Markus, Arute, Frank, Arya, Kunal, Asfaw, Abraham, Astrakhantsev, Nikita, Atalaya, Juan, Babbush, Ryan, Bacon, Dave, Ballard, Brian, Bardin, Joseph C., Bausch, Johannes, Bengtsson, Andreas, Bilmes, Alexander, Blackwell, Sam, Boixo, Sergio, Bortoli, Gina, Bourassa, Alexandre, Bovaird, Jenna, Brill, Leon, Broughton, Michael, Browne, David A., Buchea, Brett, Buckley, Bob B., Buell, David A., Burger, Tim, Burkett, Brian, Bushnell, Nicholas, Cabrera, Anthony, Campero, Juan, Chang, Hung-Shen, Chen, Yu, Chen, Zijun, Chiaro, Ben, Chik, Desmond, Chou, Charina, Claes, Jahan, Cleland, Agnetta Y., Cogan, Josh, Collins, Roberto, Conner, Paul, Courtney, William, Crook, Alexander L., Curtin, Ben, Das, Sayan, Davies, Alex, De Lorenzo, Laura, Debroy, Dripto M., Demura, Sean, Devoret, Michel, Di Paolo, Agustin, Donohoe, Paul, Drozdov, Ilya, Dunsworth, Andrew, Earle, Clint, Edlich, Thomas, Eickbusch, Alec, Elbag, Aviv Moshe, Elzouka, Mahmoud, Erickson, Catherine, Faoro, Lara, Farhi, Edward, Ferreira, Vinicius S., Burgos, Leslie Flores, Forati, Ebrahim, Fowler, Austin G., Foxen, Brooks, Ganjam, Suhas, Garcia, Gonzalo, Gasca, Robert, Genois, Élie, Giang, William, Gidney, Craig, Gilboa, Dar, Gosula, Raja, Dau, Alejandro Grajales, Graumann, Dietrich, Greene, Alex, Gross, Jonathan A., Habegger, Steve, Hall, John, Hamilton, Michael C., Hansen, Monica, Harrigan, Matthew P., Harrington, Sean D., Heras, Francisco J. H., Heslin, Stephen, Heu, Paula, Higgott, Oscar, Hill, Gordon, Hilton, Jeremy, Holland, George, Hong, Sabrina, Huang, Hsin-Yuan, Huff, Ashley, Huggins, William J., Ioffe, Lev B., Isakov, Sergei V., Iveland, Justin, Jeffrey, Evan, Jiang, Zhang, Jones, Cody, Jordan, Stephen, Joshi, Chaitali, Juhas, Pavol, Kafri, Dvir, Kang, Hui, Karamlou, Amir H., Kechedzhi, Kostyantyn, Kelly, Julian, Khaire, Trupti, Khattar, Tanuj, Khezri, Mostafa, Kim, Seon, Klimov, Paul V., Klots, Andrey R., Kobrin, Bryce, Kohli, Pushmeet, Korotkov, Alexander N., Kostritsa, Fedor, Kothari, Robin, Kozlovskii, Borislav, Kreikebaum, John Mark, Kurilovich, Vladislav D., Lacroix, Nathan, Landhuis, David, Lange-Dei, Tiano, Langley, Brandon W., Laptev, Pavel, Lau, Kim-Ming, Guevel, Loïck Le, Ledford, Justin, Lee, Kenny, Lensky, Yuri D., Leon, Shannon, Lester, Brian J., Li, Wing Yan, Li, Yin, Lill, Alexander T., Liu, Wayne, Livingston, William P., Locharla, Aditya, Lucero, Erik, Lundahl, Daniel, Lunt, Aaron, Madhuk, Sid, Malone, Fionn D., Maloney, Ashley, Mandrá, Salvatore, Martin, Leigh S., Martin, Steven, Martin, Orion, Maxfield, Cameron, McClean, Jarrod R., McEwen, Matt, Meeks, Seneca, Megrant, Anthony, Mi, Xiao, Miao, Kevin C., Mieszala, Amanda, Molavi, Reza, Molina, Sebastian, Montazeri, Shirin, Morvan, Alexis, Movassagh, Ramis, Mruczkiewicz, Wojciech, Naaman, Ofer, Neeley, Matthew, Neill, Charles, Nersisyan, Ani, Neven, Hartmut, Newman, Michael, Ng, Jiun How, Nguyen, Anthony, Nguyen, Murray, Ni, Chia-Hung, O'Brien, Thomas E., Oliver, William D., Opremcak, Alex, Ottosson, Kristoffer, Petukhov, Andre, Pizzuto, Alex, Platt, John, Potter, Rebecca, Pritchard, Orion, Pryadko, Leonid P., Quintana, Chris, Ramachandran, Ganesh, Reagor, Matthew J., Rhodes, David M., Roberts, Gabrielle, Rosenberg, Eliott, Rosenfeld, Emma, Roushan, Pedram, Rubin, Nicholas C., Saei, Negar, Sank, Daniel, Sankaragomathi, Kannan, Satzinger, Kevin J., Schurkus, Henry F., Schuster, Christopher, Senior, Andrew W., Shearn, Michael J., Shorter, Aaron, Shutty, Noah, Shvarts, Vladimir, Singh, Shraddha, Sivak, Volodymyr, Skruzny, Jindra, Small, Spencer, Smelyanskiy, Vadim, Smith, W. Clarke, Somma, Rolando D., Springer, Sofia, Sterling, George, Strain, Doug, Suchard, Jordan, Szasz, Aaron, Sztein, Alex, Thor, Douglas, Torres, Alfredo, Torunbalci, M. Mert, Vaishnav, Abeer, Vargas, Justin, Vdovichev, Sergey, Vidal, Guifre, Villalonga, Benjamin, Heidweiller, Catherine Vollgraff, Waltman, Steven, Wang, Shannon X., Ware, Brayden, Weber, Kate, White, Theodore, Wong, Kristi, Woo, Bryan W. K., Xing, Cheng, Yao, Z. Jamie, Yeh, Ping, Ying, Bicheng, Yoo, Juhwan, Yosri, Noureldin, Young, Grayson, Zalcman, Adam, Zhang, Yaxing, Zhu, Ningfeng, and Zobrist, Nicholas
Subjects: Quantum Physics
Abstract: Quantum error correction provides a path to reach practical quantum computing by combining multiple physical qubits into a logical qubit, where the logical error rate is suppressed exponentially as more qubits are added. However, this exponential suppression only occurs if the physical error rate is below a critical threshold. In this work, we present two surface code memories operating below this threshold: a distance-7 code and a distance-5 code integrated with a real-time decoder. The logical error rate of our larger quantum memory is suppressed by a factor of $\Lambda$ = 2.14 $\pm$ 0.02 when increasing the code distance by two, culminating in a 101-qubit distance-7 code with 0.143% $\pm$ 0.003% error per cycle of error correction. This logical memory is also beyond break-even, exceeding its best physical qubit's lifetime by a factor of 2.4 $\pm$ 0.3. We maintain below-threshold performance when decoding in real time, achieving an average decoder latency of 63 $\mu$s at distance-5 up to a million cycles, with a cycle time of 1.1 $\mu$s. To probe the limits of our error-correction performance, we run repetition codes up to distance-29 and find that logical performance is limited by rare correlated error events occurring approximately once every hour, or 3 $\times$ 10$^9$ cycles. Our results present device performance that, if scaled, could realize the operational requirements of large scale fault-tolerant quantum algorithms., Comment: 10 pages, 4 figures, Supplementary Information
Published: 2024

6. Thermalization and Criticality on an Analog-Digital Quantum Simulator

Author: Andersen, Trond I., Astrakhantsev, Nikita, Karamlou, Amir H., Berndtsson, Julia, Motruk, Johannes, Szasz, Aaron, Gross, Jonathan A., Schuckert, Alexander, Westerhout, Tom, Zhang, Yaxing, Forati, Ebrahim, Rossi, Dario, Kobrin, Bryce, Di Paolo, Agustin, Klots, Andrey R., Drozdov, Ilya, Kurilovich, Vladislav D., Petukhov, Andre, Ioffe, Lev B., Elben, Andreas, Rath, Aniket, Vitale, Vittorio, Vermersch, Benoit, Acharya, Rajeev, Beni, Laleh Aghababaie, Anderson, Kyle, Ansmann, Markus, Arute, Frank, Arya, Kunal, Asfaw, Abraham, Atalaya, Juan, Ballard, Brian, Bardin, Joseph C., Bengtsson, Andreas, Bilmes, Alexander, Bortoli, Gina, Bourassa, Alexandre, Bovaird, Jenna, Brill, Leon, Broughton, Michael, Browne, David A., Buchea, Brett, Buckley, Bob B., Buell, David A., Burger, Tim, Burkett, Brian, Bushnell, Nicholas, Cabrera, Anthony, Campero, Juan, Chang, Hung-Shen, Chen, Zijun, Chiaro, Ben, Claes, Jahan, Cleland, Agnetta Y., Cogan, Josh, Collins, Roberto, Conner, Paul, Courtney, William, Crook, Alexander L., Das, Sayan, Debroy, Dripto M., De Lorenzo, Laura, Barba, Alexander Del Toro, Demura, Sean, Donohoe, Paul, Dunsworth, Andrew, Earle, Clint, Eickbusch, Alec, Elbag, Aviv Moshe, Elzouka, Mahmoud, Erickson, Catherine, Faoro, Lara, Fatemi, Reza, Ferreira, Vinicius S., Burgos, Leslie Flores, Fowler, Austin G., Foxen, Brooks, Ganjam, Suhas, Gasca, Robert, Giang, William, Gidney, Craig, Gilboa, Dar, Giustina, Marissa, Gosula, Raja, Dau, Alejandro Grajales, Graumann, Dietrich, Greene, Alex, Habegger, Steve, Hamilton, Michael C., Hansen, Monica, Harrigan, Matthew P., Harrington, Sean D., Heslin, Stephen, Heu, Paula, Hill, Gordon, Hoffmann, Markus R., Huang, Hsin-Yuan, Huang, Trent, Huff, Ashley, Huggins, William J., Isakov, Sergei V., Jeffrey, Evan, Jiang, Zhang, Jones, Cody, Jordan, Stephen, Joshi, Chaitali, Juhas, Pavol, Kafri, Dvir, Kang, Hui, Kechedzhi, Kostyantyn, Khaire, Trupti, Khattar, Tanuj, Khezri, Mostafa, Kieferová, Mária, Kim, Seon, Kitaev, Alexei, Klimov, Paul V., Korotkov, Alexander N., Kostritsa, Fedor, Kreikebaum, John Mark, Landhuis, David, Langley, Brandon W., Laptev, Pavel, Lau, Kim-Ming, Guevel, Loïck Le, Ledford, Justin, Lee, Joonho, Lee, Kenny, Lensky, Yuri D., Lester, Brian J., Li, Wing Yan, Lill, Alexander T., Liu, Wayne, Livingston, William P., Locharla, Aditya, Lundahl, Daniel, Lunt, Aaron, Madhuk, Sid, Maloney, Ashley, Mandrà, Salvatore, Martin, Leigh S., Martin, Orion, Martin, Steven, Maxfield, Cameron, McClean, Jarrod R., McEwen, Matt, Meeks, Seneca, Miao, Kevin C., Mieszala, Amanda, Molina, Sebastian, Montazeri, Shirin, Morvan, Alexis, Movassagh, Ramis, Neill, Charles, Nersisyan, Ani, Newman, Michael, Nguyen, Anthony, Nguyen, Murray, Ni, Chia-Hung, Niu, Murphy Yuezhen, Oliver, William D., Ottosson, Kristoffer, Pizzuto, Alex, Potter, Rebecca, Pritchard, Orion, Pryadko, Leonid P., Quintana, Chris, Reagor, Matthew J., Rhodes, David M., Roberts, Gabrielle, Rocque, Charles, Rosenberg, Eliott, Rubin, Nicholas C., Saei, Negar, Sankaragomathi, Kannan, Satzinger, Kevin J., Schurkus, Henry F., Schuster, Christopher, Shearn, Michael J., Shorter, Aaron, Shutty, Noah, Shvarts, Vladimir, Sivak, Volodymyr, Skruzny, Jindra, Small, Spencer, Smith, W. Clarke, Springer, Sofia, Sterling, George, Suchard, Jordan, Szalay, Marco, Sztein, Alex, Thor, Douglas, Torres, Alfredo, Torunbalci, M. Mert, Vaishnav, Abeer, Vdovichev, Sergey, Villalonga, Benjamin, Heidweiller, Catherine Vollgraff, Waltman, Steven, Wang, Shannon X., White, Theodore, Wong, Kristi, Woo, Bryan W., Xing, Cheng, Yao, Z. Jamie, Yeh, Ping, Ying, Bicheng, Yoo, Juhwan, Yosri, Noureldin, Young, Grayson, Zalcman, Adam, Zhu, Ningfeng, Zobrist, Nicholas, Neven, Hartmut, Babbush, Ryan, Boixo, Sergio, Hilton, Jeremy, Lucero, Erik, Megrant, Anthony, Kelly, Julian, Chen, Yu, Smelyanskiy, Vadim, Vidal, Guifre, Roushan, Pedram, Lauchli, Andreas M., Abanin, Dmitry A., and Mi, Xiao
Subjects: Quantum Physics, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Strongly Correlated Electrons
Abstract: Understanding how interacting particles approach thermal equilibrium is a major challenge of quantum simulators. Unlocking the full potential of such systems toward this goal requires flexible initial state preparation, precise time evolution, and extensive probes for final state characterization. We present a quantum simulator comprising 69 superconducting qubits which supports both universal quantum gates and high-fidelity analog evolution, with performance beyond the reach of classical simulation in cross-entropy benchmarking experiments. Emulating a two-dimensional (2D) XY quantum magnet, we leverage a wide range of measurement techniques to study quantum states after ramps from an antiferromagnetic initial state. We observe signatures of the classical Kosterlitz-Thouless phase transition, as well as strong deviations from Kibble-Zurek scaling predictions attributed to the interplay between quantum and classical coarsening of the correlated domains. This interpretation is corroborated by injecting variable energy density into the initial state, which enables studying the effects of the eigenstate thermalization hypothesis (ETH) in targeted parts of the eigenspectrum. Finally, we digitally prepare the system in pairwise-entangled dimer states and image the transport of energy and vorticity during thermalization. These results establish the efficacy of superconducting analog-digital quantum processors for preparing states across many-body spectra and unveiling their thermalization dynamics.
Published: 2024

7. Learning high-accuracy error decoding for quantum processors

Author: Bausch, Johannes, Senior, Andrew W., Heras, Francisco J. H., Edlich, Thomas, Davies, Alex, Newman, Michael, Jones, Cody, Satzinger, Kevin, Niu, Murphy Yuezhen, Blackwell, Sam, Holland, George, Kafri, Dvir, Atalaya, Juan, Gidney, Craig, Hassabis, Demis, Boixo, Sergio, Neven, Hartmut, and Kohli, Pushmeet
Published: 2024
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8. Optimizing quantum gates towards the scale of logical qubits

Author: Klimov, Paul V., Bengtsson, Andreas, Quintana, Chris, Bourassa, Alexandre, Hong, Sabrina, Dunsworth, Andrew, Satzinger, Kevin J., Livingston, William P., Sivak, Volodymyr, Niu, Murphy Y., Andersen, Trond I., Zhang, Yaxing, Chik, Desmond, Chen, Zijun, Neill, Charles, Erickson, Catherine, Dau, Alejandro Grajales, Megrant, Anthony, Roushan, Pedram, Korotkov, Alexander N., Kelly, Julian, Smelyanskiy, Vadim, Chen, Yu, and Neven, Hartmut
Subjects: Quantum Physics
Abstract: A foundational assumption of quantum error correction theory is that quantum gates can be scaled to large processors without exceeding the error-threshold for fault tolerance. Two major challenges that could become fundamental roadblocks are manufacturing high performance quantum hardware and engineering a control system that can reach its performance limits. The control challenge of scaling quantum gates from small to large processors without degrading performance often maps to non-convex, high-constraint, and time-dependent control optimization over an exponentially expanding configuration space. Here we report on a control optimization strategy that can scalably overcome the complexity of such problems. We demonstrate it by choreographing the frequency trajectories of 68 frequency-tunable superconducting qubits to execute single- and two-qubit gates while mitigating computational errors. When combined with a comprehensive model of physical errors across our processor, the strategy suppresses physical error rates by $\sim3.7\times$ compared with the case of no optimization. Furthermore, it is projected to achieve a similar performance advantage on a distance-23 surface code logical qubit with 1057 physical qubits. Our control optimization strategy solves a generic scaling challenge in a way that can be adapted to a variety of quantum operations, algorithms, and computing architectures.
Published: 2023
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9. Model-based Optimization of Superconducting Qubit Readout

Author: Bengtsson, Andreas, Opremcak, Alex, Khezri, Mostafa, Sank, Daniel, Bourassa, Alexandre, Satzinger, Kevin J., Hong, Sabrina, Erickson, Catherine, Lester, Brian J., Miao, Kevin C., Korotkov, Alexander N., Kelly, Julian, Chen, Zijun, and Klimov, Paul V.
Subjects: Quantum Physics, Condensed Matter - Superconductivity
Abstract: Measurement is an essential component of quantum algorithms, and for superconducting qubits it is often the most error prone. Here, we demonstrate model-based readout optimization achieving low measurement errors while avoiding detrimental side-effects. For simultaneous and mid-circuit measurements across 17 qubits, we observe 1.5% error per qubit with a 500ns end-to-end duration and minimal excess reset error from residual resonator photons. We also suppress measurement-induced state transitions achieving a leakage rate limited by natural heating. This technique can scale to hundreds of qubits and be used to enhance the performance of error-correcting codes and near-term applications.
Published: 2023
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10. Dynamics of magnetization at infinite temperature in a Heisenberg spin chain

Author: Rosenberg, Eliott, Andersen, Trond, Samajdar, Rhine, Petukhov, Andre, Hoke, Jesse, Abanin, Dmitry, Bengtsson, Andreas, Drozdov, Ilya, Erickson, Catherine, Klimov, Paul, Mi, Xiao, Morvan, Alexis, Neeley, Matthew, Neill, Charles, Acharya, Rajeev, Allen, Richard, Anderson, Kyle, Ansmann, Markus, Arute, Frank, Arya, Kunal, Asfaw, Abraham, Atalaya, Juan, Bardin, Joseph, Bilmes, A., Bortoli, Gina, Bourassa, Alexandre, Bovaird, Jenna, Brill, Leon, Broughton, Michael, Buckley, Bob B., Buell, David, Burger, Tim, Burkett, Brian, Bushnell, Nicholas, Campero, Juan, Chang, Hung-Shen, Chen, Zijun, Chiaro, Benjamin, Chik, Desmond, Cogan, Josh, Collins, Roberto, Conner, Paul, Courtney, William, Crook, Alexander, Curtin, Ben, Debroy, Dripto, Barba, Alexander Del Toro, Demura, Sean, Di Paolo, Agustin, Dunsworth, Andrew, Earle, Clint, Farhi, E., Fatemi, Reza, Ferreira, Vinicius, Flores, Leslie, Forati, Ebrahim, Fowler, Austin, Foxen, Brooks, Garcia, Gonzalo, Genois, Élie, Giang, William, Gidney, Craig, Gilboa, Dar, Giustina, Marissa, Gosula, Raja, Dau, Alejandro Grajales, Gross, Jonathan, Habegger, Steve, Hamilton, Michael, Hansen, Monica, Harrigan, Matthew, Harrington, Sean, Heu, Paula, Hill, Gordon, Hoffmann, Markus, Hong, Sabrina, Huang, Trent, Huff, Ashley, Huggins, William, Ioffe, Lev, Isakov, Sergei, Iveland, Justin, Jeffrey, Evan, Jiang, Zhang, Jones, Cody, Juhas, Pavol, Kafri, D., Khattar, Tanuj, Khezri, Mostafa, Kieferová, Mária, Kim, Seon, Kitaev, Alexei, Klots, Andrey, Korotkov, Alexander, Kostritsa, Fedor, Kreikebaum, John Mark, Landhuis, David, Laptev, Pavel, Lau, Kim Ming, Laws, Lily, Lee, Joonho, Lee, Kenneth, Lensky, Yuri, Lester, Brian, Lill, Alexander, Liu, Wayne, Livingston, William P., Locharla, A., Mandrà, Salvatore, Martin, Orion, Martin, Steven, McClean, Jarrod, McEwen, Matthew, Meeks, Seneca, Miao, Kevin, Mieszala, Amanda, Montazeri, Shirin, Movassagh, Ramis, Mruczkiewicz, Wojciech, Nersisyan, Ani, Newman, Michael, Ng, Jiun How, Nguyen, Anthony, Nguyen, Murray, Niu, M., O'Brien, Thomas, Omonije, Seun, Opremcak, Alex, Potter, Rebecca, Pryadko, Leonid, Quintana, Chris, Rhodes, David, Rocque, Charles, Rubin, N., Saei, Negar, Sank, Daniel, Sankaragomathi, Kannan, Satzinger, Kevin, Schurkus, Henry, Schuster, Christopher, Shearn, Michael, Shorter, Aaron, Shutty, Noah, Shvarts, Vladimir, Sivak, Volodymyr, Skruzny, Jindra, Smith, Clarke, Somma, Rolando, Sterling, George, Strain, Doug, Szalay, Marco, Thor, Douglas, Torres, Alfredo, Vidal, Guifre, Villalonga, Benjamin, Heidweiller, Catherine Vollgraff, White, Theodore, Woo, Bryan, Xing, Cheng, Yao, Jamie, Yeh, Ping, Yoo, Juhwan, Young, Grayson, Zalcman, Adam, Zhang, Yaxing, Zhu, Ningfeng, Zobrist, Nicholas, Neven, Hartmut, Babbush, Ryan, Bacon, Dave, Boixo, Sergio, Hilton, Jeremy, Lucero, Erik, Megrant, Anthony, Kelly, Julian, Chen, Yu, Smelyanskiy, Vadim, Khemani, Vedika, Gopalakrishnan, Sarang, Prosen, Tomaž, and Roushan, Pedram
Subjects: Quantum Physics
Abstract: Understanding universal aspects of quantum dynamics is an unresolved problem in statistical mechanics. In particular, the spin dynamics of the 1D Heisenberg model were conjectured to belong to the Kardar-Parisi-Zhang (KPZ) universality class based on the scaling of the infinite-temperature spin-spin correlation function. In a chain of 46 superconducting qubits, we study the probability distribution, $P(\mathcal{M})$, of the magnetization transferred across the chain's center. The first two moments of $P(\mathcal{M})$ show superdiffusive behavior, a hallmark of KPZ universality. However, the third and fourth moments rule out the KPZ conjecture and allow for evaluating other theories. Our results highlight the importance of studying higher moments in determining dynamic universality classes and provide key insights into universal behavior in quantum systems.
Published: 2023
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11. Measurement-induced entanglement and teleportation on a noisy quantum processor

Author: Hoke, Jesse C., Ippoliti, Matteo, Rosenberg, Eliott, Abanin, Dmitry, Acharya, Rajeev, Andersen, Trond I., Ansmann, Markus, Arute, Frank, Arya, Kunal, Asfaw, Abraham, Atalaya, Juan, Bardin, Joseph C., Bengtsson, Andreas, Bortoli, Gina, Bourassa, Alexandre, Bovaird, Jenna, Brill, Leon, Broughton, Michael, Buckley, Bob B., Buell, David A., Burger, Tim, Burkett, Brian, Bushnell, Nicholas, Chen, Zijun, Chiaro, Ben, Chik, Desmond, Cogan, Josh, Collins, Roberto, Conner, Paul, Courtney, William, Crook, Alexander L., Curtin, Ben, Dau, Alejandro Grajales, Debroy, Dripto M., Barba, Alexander Del Toro, Demura, Sean, Di Paolo, Augustin, Drozdov, Ilya K., Dunsworth, Andrew, Eppens, Daniel, Erickson, Catherine, Farhi, Edward, Fatemi, Reza, Ferreira, Vinicius S., Burgos, Leslie Flores, Forati, Ebrahim, Fowler, Austin G., Foxen, Brooks, Giang, William, Gidney, Craig, Gilboa, Dar, Giustina, Marissa, Gosula, Raja, Gross, Jonathan A., Habegger, Steve, Hamilton, Michael C., Hansen, Monica, Harrigan, Matthew P., Harrington, Sean D., Heu, Paula, Hoffmann, Markus R., Hong, Sabrina, Huang, Trent, Huff, Ashley, Huggins, William J., Isakov, Sergei V., Iveland, Justin, Jeffrey, Evan, Jones, Cody, Juhas, Pavol, Kafri, Dvir, Kechedzhi, Kostyantyn, Khattar, Tanuj, Khezri, Mostafa, Kieferová, Mária, Kim, Seon, Kitaev, Alexei, Klimov, Paul V., Klots, Andrey R., Korotkov, Alexander N., Kostritsa, Fedor, Kreikebaum, John Mark, Landhuis, David, Laptev, Pavel, Lau, Kim-Ming, Laws, Lily, Lee, Joonho, Lee, Kenny W., Lensky, Yuri D., Lester, Brian J., Lill, Alexander T., Liu, Wayne, Locharla, Aditya, Martin, Orion, McClean, Jarrod R., McEwen, Matt, Miao, Kevin C., Mieszala, Amanda, Montazeri, Shirin, Morvan, Alexis, Movassagh, Ramis, Mruczkiewicz, Wojciech, Neeley, Matthew, Neill, Charles, Nersisyan, Ani, Newman, Michael, Ng, Jiun H., Nguyen, Anthony, Nguyen, Murray, Niu, Murphy Yuezhen, O'Brien, Tom E., Omonije, Seun, Opremcak, Alex, Petukhov, Andre, Potter, Rebecca, Pryadko, Leonid P., Quintana, Chris, Rocque, Charles, Rubin, Nicholas C., Saei, Negar, Sank, Daniel, Sankaragomathi, Kannan, Satzinger, Kevin J., Schurkus, Henry F., Schuster, Christopher, Shearn, Michael J., Shorter, Aaron, Shutty, Noah, Shvarts, Vlad, Skruzny, Jindra, Smith, W. Clarke, Somma, Rolando D., Sterling, George, Strain, Douglas, Szalay, Marco, Torres, Alfredo, Vidal, Guifre, Villalonga, Benjamin, Heidweiller, Catherine Vollgraff, White, Ted, Woo, Bryan W. K., Xing, Cheng, Yao, Z. Jamie., Yeh, Ping, Yoo, Juhwan, Young, Grayson, Zalcman, Adam, Zhang, Yaxing, Zhu, Ningfeng, Zobrist, Nicholas, Neven, Harmut, Babbush, Ryan, Bacon, Dave, Boixo, Sergio, Hilton, Jeremy, Lucero, Erik, Megrant, Anthony, Kelly, Julian, Chen, Yu, Smelyanskiy, Vadim, Mi, Xiao, Khemani, Vedika, and Roushan, Pedram
Subjects: Quantum Physics, Condensed Matter - Statistical Mechanics, High Energy Physics - Theory
Abstract: Measurement has a special role in quantum theory: by collapsing the wavefunction it can enable phenomena such as teleportation and thereby alter the "arrow of time" that constrains unitary evolution. When integrated in many-body dynamics, measurements can lead to emergent patterns of quantum information in space-time that go beyond established paradigms for characterizing phases, either in or out of equilibrium. On present-day NISQ processors, the experimental realization of this physics is challenging due to noise, hardware limitations, and the stochastic nature of quantum measurement. Here we address each of these experimental challenges and investigate measurement-induced quantum information phases on up to 70 superconducting qubits. By leveraging the interchangeability of space and time, we use a duality mapping, to avoid mid-circuit measurement and access different manifestations of the underlying phases -- from entanglement scaling to measurement-induced teleportation -- in a unified way. We obtain finite-size signatures of a phase transition with a decoding protocol that correlates the experimental measurement record with classical simulation data. The phases display sharply different sensitivity to noise, which we exploit to turn an inherent hardware limitation into a useful diagnostic. Our work demonstrates an approach to realize measurement-induced physics at scales that are at the limits of current NISQ processors.
Published: 2023
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12. Overcoming leakage in scalable quantum error correction

Author: Miao, Kevin C., McEwen, Matt, Atalaya, Juan, Kafri, Dvir, Pryadko, Leonid P., Bengtsson, Andreas, Opremcak, Alex, Satzinger, Kevin J., Chen, Zijun, Klimov, Paul V., Quintana, Chris, Acharya, Rajeev, Anderson, Kyle, Ansmann, Markus, Arute, Frank, Arya, Kunal, Asfaw, Abraham, Bardin, Joseph C., Bourassa, Alexandre, Bovaird, Jenna, Brill, Leon, Buckley, Bob B., Buell, David A., Burger, Tim, Burkett, Brian, Bushnell, Nicholas, Campero, Juan, Chiaro, Ben, Collins, Roberto, Conner, Paul, Crook, Alexander L., Curtin, Ben, Debroy, Dripto M., Demura, Sean, Dunsworth, Andrew, Erickson, Catherine, Fatemi, Reza, Ferreira, Vinicius S., Burgos, Leslie Flores, Forati, Ebrahim, Fowler, Austin G., Foxen, Brooks, Garcia, Gonzalo, Giang, William, Gidney, Craig, Giustina, Marissa, Gosula, Raja, Dau, Alejandro Grajales, Gross, Jonathan A., Hamilton, Michael C., Harrington, Sean D., Heu, Paula, Hilton, Jeremy, Hoffmann, Markus R., Hong, Sabrina, Huang, Trent, Huff, Ashley, Iveland, Justin, Jeffrey, Evan, Jiang, Zhang, Jones, Cody, Kelly, Julian, Kim, Seon, Kostritsa, Fedor, Kreikebaum, John Mark, Landhuis, David, Laptev, Pavel, Laws, Lily, Lee, Kenny, Lester, Brian J., Lill, Alexander T., Liu, Wayne, Locharla, Aditya, Lucero, Erik, Martin, Steven, Megrant, Anthony, Mi, Xiao, Montazeri, Shirin, Morvan, Alexis, Naaman, Ofer, Neeley, Matthew, Neill, Charles, Nersisyan, Ani, Newman, Michael, Ng, Jiun How, Nguyen, Anthony, Nguyen, Murray, Potter, Rebecca, Rocque, Charles, Roushan, Pedram, Sankaragomathi, Kannan, Schuster, Christopher, Shearn, Michael J., Shorter, Aaron, Shutty, Noah, Shvarts, Vladimir, Skruzny, Jindra, Smith, W. Clarke, Sterling, George, Szalay, Marco, Thor, Douglas, Torres, Alfredo, White, Theodore, Woo, Bryan W. K., Yao, Z. Jamie, Yeh, Ping, Yoo, Juhwan, Young, Grayson, Zalcman, Adam, Zhu, Ningfeng, Zobrist, Nicholas, Neven, Hartmut, Smelyanskiy, Vadim, Petukhov, Andre, Korotkov, Alexander N., Sank, Daniel, and Chen, Yu
Subjects: Quantum Physics
Abstract: Leakage of quantum information out of computational states into higher energy states represents a major challenge in the pursuit of quantum error correction (QEC). In a QEC circuit, leakage builds over time and spreads through multi-qubit interactions. This leads to correlated errors that degrade the exponential suppression of logical error with scale, challenging the feasibility of QEC as a path towards fault-tolerant quantum computation. Here, we demonstrate the execution of a distance-3 surface code and distance-21 bit-flip code on a Sycamore quantum processor where leakage is removed from all qubits in each cycle. This shortens the lifetime of leakage and curtails its ability to spread and induce correlated errors. We report a ten-fold reduction in steady-state leakage population on the data qubits encoding the logical state and an average leakage population of less than $1 \times 10^{-3}$ throughout the entire device. The leakage removal process itself efficiently returns leakage population back to the computational basis, and adding it to a code circuit prevents leakage from inducing correlated error across cycles, restoring a fundamental assumption of QEC. With this demonstration that leakage can be contained, we resolve a key challenge for practical QEC at scale., Comment: Main text: 7 pages, 5 figures
Published: 2022
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13. Non-Abelian braiding of graph vertices in a superconducting processor

Author: Andersen, Trond I., Lensky, Yuri D., Kechedzhi, Kostyantyn, Drozdov, Ilya, Bengtsson, Andreas, Hong, Sabrina, Morvan, Alexis, Mi, Xiao, Opremcak, Alex, Acharya, Rajeev, Allen, Richard, Ansmann, Markus, Arute, Frank, Arya, Kunal, Asfaw, Abraham, Atalaya, Juan, Babbush, Ryan, Bacon, Dave, Bardin, Joseph C., Bortoli, Gina, Bourassa, Alexandre, Bovaird, Jenna, Brill, Leon, Broughton, Michael, Buckley, Bob B., Buell, David A., Burger, Tim, Burkett, Brian, Bushnell, Nicholas, Chen, Zijun, Chiaro, Ben, Chik, Desmond, Chou, Charina, Cogan, Josh, Collins, Roberto, Conner, Paul, Courtney, William, Crook, Alexander L., Curtin, Ben, Debroy, Dripto M., Barba, Alexander Del Toro, Demura, Sean, Dunsworth, Andrew, Eppens, Daniel, Erickson, Catherine, Faoro, Lara, Farhi, Edward, Fatemi, Reza, Ferreira, Vinicius S., Burgos, Leslie Flores, Forati, Ebrahim, Fowler, Austin G., Foxen, Brooks, Giang, William, Gidney, Craig, Gilboa, Dar, Giustina, Marissa, Gosula, Raja, Dau, Alejandro Grajales, Gross, Jonathan A., Habegger, Steve, Hamilton, Michael C., Hansen, Monica, Harrigan, Matthew P., Harrington, Sean D., Heu, Paula, Hilton, Jeremy, Hoffmann, Markus R., Huang, Trent, Huff, Ashley, Huggins, William J., Ioffe, Lev B., Isakov, Sergei V., Iveland, Justin, Jeffrey, Evan, Jiang, Zhang, Jones, Cody, Juhas, Pavol, Kafri, Dvir, Khattar, Tanuj, Khezri, Mostafa, Kieferová, Mária, Kim, Seon, Kitaev, Alexei, Klimov, Paul V., Klots, Andrey R., Korotkov, Alexander N., Kostritsa, Fedor, Kreikebaum, John Mark, Landhuis, David, Laptev, Pavel, Lau, Kim-Ming, Laws, Lily, Lee, Joonho, Lee, Kenny, Lester, Brian J., Lill, Alexander, Liu, Wayne, Locharla, Aditya, Lucero, Erik, Malone, Fionn D., Martin, Orion, McClean, Jarrod R., McCourt, Trevor, McEwen, Matt, Miao, Kevin C., Mieszala, Amanda, Mohseni, Masoud, Montazeri, Shirin, Mount, Emily, Movassagh, Ramis, Mruczkiewicz, Wojciech, Naaman, Ofer, Neeley, Matthew, Neill, Charles, Nersisyan, Ani, Newman, Michael, Ng, Jiun How, Nguyen, Anthony, Nguyen, Murray, Niu, Murphy Yuezhen, O'Brien, Thomas E., Omonije, Seun, Petukhov, Andre, Potter, Rebecca, Pryadko, Leonid P., Quintana, Chris, Rocque, Charles, Rubin, Nicholas C., Saei, Negar, Sank, Daniel, Sankaragomathi, Kannan, Satzinger, Kevin J., Schurkus, Henry F., Schuster, Christopher, Shearn, Michael J., Shorter, Aaron, Shutty, Noah, Shvarts, Vladimir, Skruzny, Jindra, Smith, W. Clarke, Somma, Rolando, Sterling, George, Strain, Doug, Szalay, Marco, Torres, Alfredo, Vidal, Guifre, Villalonga, Benjamin, Heidweiller, Catherine Vollgraff, White, Theodore, Woo, Bryan W. K., Xing, Cheng, Yao, Z. Jamie, Yeh, Ping, Yoo, Juhwan, Young, Grayson, Zalcman, Adam, Zhang, Yaxing, Zhu, Ningfeng, Zobrist, Nicholas, Neven, Hartmut, Boixo, Sergio, Megrant, Anthony, Kelly, Julian, Chen, Yu, Smelyanskiy, Vadim, Kim, Eun-Ah, Aleiner, Igor, and Roushan, Pedram
Subjects: Quantum Physics, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Other Condensed Matter
Abstract: Indistinguishability of particles is a fundamental principle of quantum mechanics. For all elementary and quasiparticles observed to date - including fermions, bosons, and Abelian anyons - this principle guarantees that the braiding of identical particles leaves the system unchanged. However, in two spatial dimensions, an intriguing possibility exists: braiding of non-Abelian anyons causes rotations in a space of topologically degenerate wavefunctions. Hence, it can change the observables of the system without violating the principle of indistinguishability. Despite the well developed mathematical description of non-Abelian anyons and numerous theoretical proposals, the experimental observation of their exchange statistics has remained elusive for decades. Controllable many-body quantum states generated on quantum processors offer another path for exploring these fundamental phenomena. While efforts on conventional solid-state platforms typically involve Hamiltonian dynamics of quasi-particles, superconducting quantum processors allow for directly manipulating the many-body wavefunction via unitary gates. Building on predictions that stabilizer codes can host projective non-Abelian Ising anyons, we implement a generalized stabilizer code and unitary protocol to create and braid them. This allows us to experimentally verify the fusion rules of the anyons and braid them to realize their statistics. We then study the prospect of employing the anyons for quantum computation and utilize braiding to create an entangled state of anyons encoding three logical qubits. Our work provides new insights about non-Abelian braiding and - through the future inclusion of error correction to achieve topological protection - could open a path toward fault-tolerant quantum computing.
Published: 2022

14. Readout of a quantum processor with high dynamic range Josephson parametric amplifiers

Author: White, T. C., Opremcak, Alex, Sterling, George, Korotkov, Alexander, Sank, Daniel, Acharya, Rajeev, Ansmann, Markus, Arute, Frank, Arya, Kunal, Bardin, Joseph C., Bengtsson, Andreas, Bourassa, Alexandre, Bovaird, Jenna, Brill, Leon, Buckley, Bob B., Buell, David A., Burger, Tim, Burkett, Brian, Bushnell, Nicholas, Chen, Zijun, Chiaro, Ben, Cogan, Josh, Collins, Roberto, Crook, Alexander L., Curtin, Ben, Demura, Sean, Dunsworth, Andrew, Erickson, Catherine, Fatemi, Reza, Flores-Burgos, Leslie, Forati, Ebrahim, Foxen, Brooks, Giang, William, Giustina, Marissa, Dau, Alejandro Grajales, Hamilton, Michael C., Harrington, Sean D., Hilton, Jeremy, Hoffmann, Markus, Hong, Sabrina, Huang, Trent, Huff, Ashley, Iveland, Justin, Jeffrey, Evan, Kieferová, Márika, Kim, Seon, Klimov, Paul V., Kostritsa, Fedor, Kreikebaum, John Mark, Landhuis, David, Laptev, Pavel, Laws, Lily, Lee, Kenny, Lester, Brian J., Lill, Alexander, Liu, Wayne, Locharla, Aditya, Lucero, Erik, McCourt, Trevor, McEwen, Matt, Mi, Xiao, Miao, Kevin C., Montazeri, Shirin, Morvan, Alexis, Neeley, Matthew, Neill, Charles, Nersisyan, Ani, Ng, Jiun How, Nguyen, Anthony, Nguyen, Murray, Potter, Rebecca, Quintana, Chris, Roushan, Pedram, Sankaragomathi, Kannan, Satzinger, Kevin J., Schuster, Christopher, Shearn, Michael J., Shorter, Aaron, Shvarts, Vladimir, Skruzny, Jindra, Smith, W. Clarke, Szalay, Marco, Torres, Alfredo, Woo, Bryan, Yao, Z. Jamie, Yeh, Ping, Yoo, Juhwan, Young, Grayson, Zhu, Ningfeng, Zobrist, Nicholas, Chen, Yu, Megrant, Anthony, Kelly, Julian, and Naaman, Ofer
Subjects: Quantum Physics, Condensed Matter - Superconductivity, Physics - Applied Physics
Abstract: We demonstrate a high dynamic range Josephson parametric amplifier (JPA) in which the active nonlinear element is implemented using an array of rf-SQUIDs. The device is matched to the 50 $\Omega$ environment with a Klopfenstein-taper impedance transformer and achieves a bandwidth of 250-300 MHz, with input saturation powers up to -95 dBm at 20 dB gain. A 54-qubit Sycamore processor was used to benchmark these devices, providing a calibration for readout power, an estimate of amplifier added noise, and a platform for comparison against standard impedance matched parametric amplifiers with a single dc-SQUID. We find that the high power rf-SQUID array design has no adverse effect on system noise, readout fidelity, or qubit dephasing, and we estimate an upper bound on amplifier added noise at 1.6 times the quantum limit. Lastly, amplifiers with this design show no degradation in readout fidelity due to gain compression, which can occur in multi-tone multiplexed readout with traditional JPAs., Comment: 10 pages, 10 figures
Published: 2022
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15. Suppressing quantum errors by scaling a surface code logical qubit

Author: Acharya, Rajeev, Aleiner, Igor, Allen, Richard, Andersen, Trond I., Ansmann, Markus, Arute, Frank, Arya, Kunal, Asfaw, Abraham, Atalaya, Juan, Babbush, Ryan, Bacon, Dave, Bardin, Joseph C., Basso, Joao, Bengtsson, Andreas, Boixo, Sergio, Bortoli, Gina, Bourassa, Alexandre, Bovaird, Jenna, Brill, Leon, Broughton, Michael, Buckley, Bob B., Buell, David A., Burger, Tim, Burkett, Brian, Bushnell, Nicholas, Chen, Yu, Chen, Zijun, Chiaro, Ben, Cogan, Josh, Collins, Roberto, Conner, Paul, Courtney, William, Crook, Alexander L., Curtin, Ben, Debroy, Dripto M., Barba, Alexander Del Toro, Demura, Sean, Dunsworth, Andrew, Eppens, Daniel, Erickson, Catherine, Faoro, Lara, Farhi, Edward, Fatemi, Reza, Burgos, Leslie Flores, Forati, Ebrahim, Fowler, Austin G., Foxen, Brooks, Giang, William, Gidney, Craig, Gilboa, Dar, Giustina, Marissa, Dau, Alejandro Grajales, Gross, Jonathan A., Habegger, Steve, Hamilton, Michael C., Harrigan, Matthew P., Harrington, Sean D., Higgott, Oscar, Hilton, Jeremy, Hoffmann, Markus, Hong, Sabrina, Huang, Trent, Huff, Ashley, Huggins, William J., Ioffe, Lev B., Isakov, Sergei V., Iveland, Justin, Jeffrey, Evan, Jiang, Zhang, Jones, Cody, Juhas, Pavol, Kafri, Dvir, Kechedzhi, Kostyantyn, Kelly, Julian, Khattar, Tanuj, Khezri, Mostafa, Kieferová, Mária, Kim, Seon, Kitaev, Alexei, Klimov, Paul V., Klots, Andrey R., Korotkov, Alexander N., Kostritsa, Fedor, Kreikebaum, John Mark, Landhuis, David, Laptev, Pavel, Lau, Kim-Ming, Laws, Lily, Lee, Joonho, Lee, Kenny, Lester, Brian J., Lill, Alexander, Liu, Wayne, Locharla, Aditya, Lucero, Erik, Malone, Fionn D., Marshall, Jeffrey, Martin, Orion, McClean, Jarrod R., Mccourt, Trevor, McEwen, Matt, Megrant, Anthony, Costa, Bernardo Meurer, Mi, Xiao, Miao, Kevin C., Mohseni, Masoud, Montazeri, Shirin, Morvan, Alexis, Mount, Emily, Mruczkiewicz, Wojciech, Naaman, Ofer, Neeley, Matthew, Neill, Charles, Nersisyan, Ani, Neven, Hartmut, Newman, Michael, Ng, Jiun How, Nguyen, Anthony, Nguyen, Murray, Niu, Murphy Yuezhen, O'Brien, Thomas E., Opremcak, Alex, Platt, John, Petukhov, Andre, Potter, Rebecca, Pryadko, Leonid P., Quintana, Chris, Roushan, Pedram, Rubin, Nicholas C., Saei, Negar, Sank, Daniel, Sankaragomathi, Kannan, Satzinger, Kevin J., Schurkus, Henry F., Schuster, Christopher, Shearn, Michael J., Shorter, Aaron, Shvarts, Vladimir, Skruzny, Jindra, Smelyanskiy, Vadim, Smith, W. Clarke, Sterling, George, Strain, Doug, Szalay, Marco, Torres, Alfredo, Vidal, Guifre, Villalonga, Benjamin, Heidweiller, Catherine Vollgraff, White, Theodore, Xing, Cheng, Yao, Z. Jamie, Yeh, Ping, Yoo, Juhwan, Young, Grayson, Zalcman, Adam, Zhang, Yaxing, and Zhu, Ningfeng
Subjects: Quantum Physics
Abstract: Practical quantum computing will require error rates that are well below what is achievable with physical qubits. Quantum error correction offers a path to algorithmically-relevant error rates by encoding logical qubits within many physical qubits, where increasing the number of physical qubits enhances protection against physical errors. However, introducing more qubits also increases the number of error sources, so the density of errors must be sufficiently low in order for logical performance to improve with increasing code size. Here, we report the measurement of logical qubit performance scaling across multiple code sizes, and demonstrate that our system of superconducting qubits has sufficient performance to overcome the additional errors from increasing qubit number. We find our distance-5 surface code logical qubit modestly outperforms an ensemble of distance-3 logical qubits on average, both in terms of logical error probability over 25 cycles and logical error per cycle ($2.914\%\pm 0.016\%$ compared to $3.028\%\pm 0.023\%$). To investigate damaging, low-probability error sources, we run a distance-25 repetition code and observe a $1.7\times10^{-6}$ logical error per round floor set by a single high-energy event ($1.6\times10^{-7}$ when excluding this event). We are able to accurately model our experiment, and from this model we can extract error budgets that highlight the biggest challenges for future systems. These results mark the first experimental demonstration where quantum error correction begins to improve performance with increasing qubit number, illuminating the path to reaching the logical error rates required for computation., Comment: Main text: 6 pages, 4 figures. v2: Update author list, references, Fig. S12, Table IV
Published: 2022

16. Formation of robust bound states of interacting microwave photons

Author: Morvan, Alexis, Andersen, Trond I., Mi, Xiao, Neill, Charles, Petukhov, Andre, Kechedzhi, Kostyantyn, Abanin, Dmitry, Acharya, Rajeev, Arute, Frank, Arya, Kunal, Asfaw, Abraham, Atalaya, Juan, Babbush, Ryan, Bacon, Dave, Bardin, Joseph C., Basso, Joao, Bengtsson, Andreas, Bortoli, Gina, Bourassa, Alexandre, Bovaird, Jenna, Brill, Leon, Broughton, Michael, Buckley, Bob B., Buell, David A., Burger, Tim, Burkett, Brian, Bushnell, Nicholas, Chen, Zijun, Chiaro, Ben, Collins, Roberto, Conner, Paul, Courtney, William, Crook, Alexander L., Curtin, Ben, Debroy, Dripto M., Barba, Alexander Del Toro, Demura, Sean, Dunsworth, Andrew, Eppens, Daniel, Erickson, Catherine, Faoro, Lara, Farhi, Edward, Fatemi, Reza, Burgos, Leslie Flores, Forati, Ebrahim, Fowler, Austin G., Foxen, Brooks, Giang, William, Gidney, Craig, Gilboa, Dar, Giustina, Marissa, Dau, Alejandro Grajales, Gross, Jonathan A., Habegger, Steve, Hamilton, Michael C., Harrigan, Matthew P., Harrington, Sean D., Hilton, Jeremy, Hoffmann, Markus, Hong, Sabrina, Huang, Trent, Huff, Ashley, Huggins, William J., Isakov, Sergei V., Iveland, Justin, Jeffrey, Evan, Jiang, Zhang, Jones, Cody, Juhas, Pavol, Kafri, Dvir, Khattar, Tanuj, Khezri, Mostafa, Kieferova, Marika, Kim, Seon, Kitaev, Alexei, Klimov, Paul V., Klots, Andrey R., Korotkov, Alexander N., Kostritsa, Fedor, Kreikebaum, John Mark, Landhuis, David, Laptev, Pavel, Lau, Kim-Ming, Laws, Lily, Lee, Joonho, Lee, Kenny, Lester, Brian J., Lill, Alexander, Liu, Wayne, Locharla, Aditya, Lucero, Erik, Malone, Fionn D., Martin, Orion, McClean, Jarrod R., McEwen, Matt, Costa, Bernardo Meurer, Miao, Kevin C., Mohseni, Masoud, Montazeri, Shirin, Mount, Emily, Mruczkiewicz, Wojciech, Naaman, Ofer, Neeley, Matthew, Nersisyan, Ani, Newman, Michael, Nguyen, Anthony, Nguyen, Murray, Niu, Murphy Yuezhen, O'Brien, Thomas E., Olenewa, Ricardo, Opremcak, Alex, Potter, Rebecca, Quintana, Chris, Rubin, Nicholas C., Saei, Negar, Sank, Daniel, Sankaragomathi, Kannan, Satzinger, Kevin J., Schurkus, Henry F., Schuster, Christopher, Shearn, Michael J., Shorter, Aaron, Shvarts, Vladimir, Skruzny, Jindra, Smith, W. Clarke, Sterling, George, Strain, Doug, Su, Yuan, Szalay, Marco, Torres, Alfredo, Vidal, Guifre, Villalonga, Benjamin, Heidweiller, Catherine Vollgraff, White, Theodore, Xing, Cheng, Yao, Z. Jamie, Yeh, Ping, Yoo, Juhwan, Zalcman, Adam, Zhang, Yaxing, Zhu, Ningfeng, Neven, Hartmut, Boixo, Sergio, Megrant, Anthony, Kelly, Julian, Chen, Yu, Smelyanskiy, Vadim, Aleiner, Igor, Ioffe, Lev B., and Roushan, Pedram
Subjects: Quantum Physics, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Other Condensed Matter
Abstract: Systems of correlated particles appear in many fields of science and represent some of the most intractable puzzles in nature. The computational challenge in these systems arises when interactions become comparable to other energy scales, which makes the state of each particle depend on all other particles. The lack of general solutions for the 3-body problem and acceptable theory for strongly correlated electrons shows that our understanding of correlated systems fades when the particle number or the interaction strength increases. One of the hallmarks of interacting systems is the formation of multi-particle bound states. In a ring of 24 superconducting qubits, we develop a high fidelity parameterizable fSim gate that we use to implement the periodic quantum circuit of the spin-1/2 XXZ model, an archetypal model of interaction. By placing microwave photons in adjacent qubit sites, we study the propagation of these excitations and observe their bound nature for up to 5 photons. We devise a phase sensitive method for constructing the few-body spectrum of the bound states and extract their pseudo-charge by introducing a synthetic flux. By introducing interactions between the ring and additional qubits, we observe an unexpected resilience of the bound states to integrability breaking. This finding goes against the common wisdom that bound states in non-integrable systems are unstable when their energies overlap with the continuum spectrum. Our work provides experimental evidence for bound states of interacting photons and discovers their stability beyond the integrability limit., Comment: 7 pages + 15 pages supplements
Published: 2022
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17. Noise-resilient Edge Modes on a Chain of Superconducting Qubits

Author: Mi, Xiao, Sonner, Michael, Niu, Murphy Yuezhen, Lee, Kenneth W., Foxen, Brooks, Acharya, Rajeev, Aleiner, Igor, Andersen, Trond I., Arute, Frank, Arya, Kunal, Asfaw, Abraham, Atalaya, Juan, Babbush, Ryan, Bacon, Dave, Bardin, Joseph C., Basso, Joao, Bengtsson, Andreas, Bortoli, Gina, Bourassa, Alexandre, Brill, Leon, Broughton, Michael, Buckley, Bob B., Buell, David A., Burkett, Brian, Bushnell, Nicholas, Chen, Zijun, Chiaro, Benjamin, Collins, Roberto, Conner, Paul, Courtney, William, Crook, Alexander L., Debroy, Dripto M., Demura, Sean, Dunsworth, Andrew, Eppens, Daniel, Erickson, Catherine, Faoro, Lara, Farhi, Edward, Fatemi, Reza, Flores, Leslie, Forati, Ebrahim, Fowler, Austin G., Giang, William, Gidney, Craig, Gilboa, Dar, Giustina, Marissa, Dau, Alejandro Grajales, Gross, Jonathan A., Habegger, Steve, Harrigan, Matthew P., Hilton, Jeremy, Hoffmann, Markus, Hong, Sabrina, Huang, Trent, Huff, Ashley, Huggins, William J., Ioffe, Lev B., Isakov, Sergei V., Iveland, Justin, Jeffrey, Evan, Jiang, Zhang, Jones, Cody, Kafri, Dvir, Kechedzhi, Kostyantyn, Khattar, Tanuj, Kim, Seon, Kitaev, Alexei, Klimov, Paul V., Klots, Andrey R., Korotkov, Alexander N., Kostritsa, Fedor, Kreikebaum, J. M., Landhuis, David, Laptev, Pavel, Lau, Kim-Ming, Lee, Joonho, Laws, Lily, Liu, Wayne, Locharla, Aditya, Lucero, Erik, Martin, Orion, McClean, Jarrod R., McEwen, Matt, Costa, Bernardo Meurer, Miao, Kevin C., Mohseni, Masoud, Montazeri, Shirin, Morvan, Alexis, Mount, Emily, Mruczkiewicz, Wojciech, Naaman, Ofer, Neeley, Matthew, Neill, Charles, Newman, Michael, O'Brien, Thomas E., Opremcak, Alex, Petukhov, Andre, Potter, Rebecca, Quintana, Chris, Rubin, Nicholas C., Saei, Negar, Sank, Daniel, Sankaragomathi, Kannan, Satzinger, Kevin J., Schuster, Christopher, Shearn, Michael J., Shvarts, Vladimir, Strain, Doug, Su, Yuan, Szalay, Marco, Vidal, Guifre, Villalonga, Benjamin, Vollgraff-Heidweiller, Catherine, White, Theodore, Yao, Z. Jamie, Yeh, Ping, Yoo, Juhwan, Zalcman, Adam, Zhang, Yaxing, Zhu, Ningfeng, Neven, Hartmut, Boixo, Sergio, Megrant, Anthony, Chen, Yu, Kelly, Julian, Smelyanskiy, Vadim, Abanin, Dmitry A., and Roushan, Pedram
Subjects: Quantum Physics, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Other Condensed Matter
Abstract: Inherent symmetry of a quantum system may protect its otherwise fragile states. Leveraging such protection requires testing its robustness against uncontrolled environmental interactions. Using 47 superconducting qubits, we implement the one-dimensional kicked Ising model which exhibits non-local Majorana edge modes (MEMs) with $\mathbb{Z}_2$ parity symmetry. Remarkably, we find that any multi-qubit Pauli operator overlapping with the MEMs exhibits a uniform late-time decay rate comparable to single-qubit relaxation rates, irrespective of its size or composition. This characteristic allows us to accurately reconstruct the exponentially localized spatial profiles of the MEMs. Furthermore, the MEMs are found to be resilient against certain symmetry-breaking noise owing to a prethermalization mechanism. Our work elucidates the complex interplay between noise and symmetry-protected edge modes in a solid-state environment.
Published: 2022
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18. Observation of Time-Crystalline Eigenstate Order on a Quantum Processor

Author: Mi, Xiao, Ippoliti, Matteo, Quintana, Chris, Greene, Ami, Chen, Zijun, Gross, Jonathan, Arute, Frank, Arya, Kunal, Atalaya, Juan, Babbush, Ryan, Bardin, Joseph C., Basso, Joao, Bengtsson, Andreas, Bilmes, Alexander, Bourassa, Alexandre, Brill, Leon, Broughton, Michael, Buckley, Bob B., Buell, David A., Burkett, Brian, Bushnell, Nicholas, Chiaro, Benjamin, Collins, Roberto, Courtney, William, Debroy, Dripto, Demura, Sean, Derk, Alan R., Dunsworth, Andrew, Eppens, Daniel, Erickson, Catherine, Farhi, Edward, Fowler, Austin G., Foxen, Brooks, Gidney, Craig, Giustina, Marissa, Harrigan, Matthew P., Harrington, Sean D., Hilton, Jeremy, Ho, Alan, Hong, Sabrina, Huang, Trent, Huff, Ashley, Huggins, William J., Ioffe, L. B., Isakov, Sergei V., Iveland, Justin, Jeffrey, Evan, Jiang, Zhang, Jones, Cody, Kafri, Dvir, Khattar, Tanuj, Kim, Seon, Kitaev, Alexei, Klimov, Paul V., Korotkov, Alexander N., Kostritsa, Fedor, Landhuis, David, Laptev, Pavel, Lee, Joonho, Lee, Kenny, Locharla, Aditya, Lucero, Erik, Martin, Orion, McClean, Jarrod R., McCourt, Trevor, McEwen, Matt, Miao, Kevin C., Mohseni, Masoud, Montazeri, Shirin, Mruczkiewicz, Wojciech, Naaman, Ofer, Neeley, Matthew, Neill, Charles, Newman, Michael, Niu, Murphy Yuezhen, Brien, Thomas E. O\', Opremcak, Alex, Ostby, Eric, Pato, Balint, Petukhov, Andre, Rubin, Nicholas C., Sank, Daniel, Satzinger, Kevin J., Shvarts, Vladimir, Su, Yuan, Strain, Doug, Szalay, Marco, Trevithick, Matthew D., Villalonga, Benjamin, White, Theodore, Yao, Z. Jamie, Yeh, Ping, Yoo, Juhwan, Zalcman, Adam, Neven, Hartmut, Boixo, Sergio, Smelyanskiy, Vadim, Megrant, Anthony, Kelly, Julian, Chen, Yu, Sondhi, S. L., Moessner, Roderich, Kechedzhi, Kostyantyn, Khemani, Vedika, and Roushan, Pedram
Subjects: Quantum Physics, Condensed Matter - Disordered Systems and Neural Networks, Condensed Matter - Statistical Mechanics, Condensed Matter - Strongly Correlated Electrons
Abstract: Quantum many-body systems display rich phase structure in their low-temperature equilibrium states. However, much of nature is not in thermal equilibrium. Remarkably, it was recently predicted that out-of-equilibrium systems can exhibit novel dynamical phases that may otherwise be forbidden by equilibrium thermodynamics, a paradigmatic example being the discrete time crystal (DTC). Concretely, dynamical phases can be defined in periodically driven many-body localized systems via the concept of eigenstate order. In eigenstate-ordered phases, the entire many-body spectrum exhibits quantum correlations and long-range order, with characteristic signatures in late-time dynamics from all initial states. It is, however, challenging to experimentally distinguish such stable phases from transient phenomena, wherein few select states can mask typical behavior. Here we implement a continuous family of tunable CPHASE gates on an array of superconducting qubits to experimentally observe an eigenstate-ordered DTC. We demonstrate the characteristic spatiotemporal response of a DTC for generic initial states. Our work employs a time-reversal protocol that discriminates external decoherence from intrinsic thermalization, and leverages quantum typicality to circumvent the exponential cost of densely sampling the eigenspectrum. In addition, we locate the phase transition out of the DTC with an experimental finite-size analysis. These results establish a scalable approach to study non-equilibrium phases of matter on current quantum processors.
Published: 2021
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19. Resolving catastrophic error bursts from cosmic rays in large arrays of superconducting qubits

Author: McEwen, Matt, Faoro, Lara, Arya, Kunal, Dunsworth, Andrew, Huang, Trent, Kim, Seon, Burkett, Brian, Fowler, Austin, Arute, Frank, Bardin, Joseph C., Bengtsson, Andreas, Bilmes, Alexander, Buckley, Bob B., Bushnell, Nicholas, Chen, Zijun, Collins, Roberto, Demura, Sean, Derk, Alan R., Erickson, Catherine, Giustina, Marissa, Harrington, Sean D., Hong, Sabrina, Jeffrey, Evan, Kelly, Julian, Klimov, Paul V., Kostritsa, Fedor, Laptev, Pavel, Locharla, Aditya, Mi, Xiao, Miao, Kevin C., Montazeri, Shirin, Mutus, Josh, Naaman, Ofer, Neeley, Matthew, Neill, Charles, Opremcak, Alex, Quintana, Chris, Redd, Nicholas, Roushan, Pedram, Sank, Daniel, Satzinger, Kevin J., Shvarts, Vladimir, White, Theodore, Yao, Z. Jamie, Yeh, Ping, Yoo, Juhwan, Chen, Yu, Smelyanskiy, Vadim, Martinis, John M., Neven, Hartmut, Megrant, Anthony, Ioffe, Lev, and Barends, Rami
Subjects: Quantum Physics
Abstract: Scalable quantum computing can become a reality with error correction, provided coherent qubits can be constructed in large arrays. The key premise is that physical errors can remain both small and sufficiently uncorrelated as devices scale, so that logical error rates can be exponentially suppressed. However, energetic impacts from cosmic rays and latent radioactivity violate both of these assumptions. An impinging particle ionizes the substrate, radiating high energy phonons that induce a burst of quasiparticles, destroying qubit coherence throughout the device. High-energy radiation has been identified as a source of error in pilot superconducting quantum devices, but lacking a measurement technique able to resolve a single event in detail, the effect on large scale algorithms and error correction in particular remains an open question. Elucidating the physics involved requires operating large numbers of qubits at the same rapid timescales as in error correction, exposing the event's evolution in time and spread in space. Here, we directly observe high-energy rays impacting a large-scale quantum processor. We introduce a rapid space and time-multiplexed measurement method and identify large bursts of quasiparticles that simultaneously and severely limit the energy coherence of all qubits, causing chip-wide failure. We track the events from their initial localised impact to high error rates across the chip. Our results provide direct insights into the scale and dynamics of these damaging error bursts in large-scale devices, and highlight the necessity of mitigation to enable quantum computing to scale.
Published: 2021
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20. Time-crystalline eigenstate order on a quantum processor

Author: Mi, Xiao, Ippoliti, Matteo, Quintana, Chris, Greene, Ami, Chen, Zijun, Gross, Jonathan, Arute, Frank, Arya, Kunal, Atalaya, Juan, Babbush, Ryan, Bardin, Joseph C, Basso, Joao, Bengtsson, Andreas, Bilmes, Alexander, Bourassa, Alexandre, Brill, Leon, Broughton, Michael, Buckley, Bob B, Buell, David A, Burkett, Brian, Bushnell, Nicholas, Chiaro, Benjamin, Collins, Roberto, Courtney, William, Debroy, Dripto, Demura, Sean, Derk, Alan R, Dunsworth, Andrew, Eppens, Daniel, Erickson, Catherine, Farhi, Edward, Fowler, Austin G, Foxen, Brooks, Gidney, Craig, Giustina, Marissa, Harrigan, Matthew P, Harrington, Sean D, Hilton, Jeremy, Ho, Alan, Hong, Sabrina, Huang, Trent, Huff, Ashley, Huggins, William J, Ioffe, LB, Isakov, Sergei V, Iveland, Justin, Jeffrey, Evan, Jiang, Zhang, Jones, Cody, Kafri, Dvir, Khattar, Tanuj, Kim, Seon, Kitaev, Alexei, Klimov, Paul V, Korotkov, Alexander N, Kostritsa, Fedor, Landhuis, David, Laptev, Pavel, Lee, Joonho, Lee, Kenny, Locharla, Aditya, Lucero, Erik, Martin, Orion, McClean, Jarrod R, McCourt, Trevor, McEwen, Matt, Miao, Kevin C, Mohseni, Masoud, Montazeri, Shirin, Mruczkiewicz, Wojciech, Naaman, Ofer, Neeley, Matthew, Neill, Charles, Newman, Michael, Niu, Murphy Yuezhen, O’Brien, Thomas E, Opremcak, Alex, Ostby, Eric, Pato, Balint, Petukhov, Andre, Rubin, Nicholas C, Sank, Daniel, Satzinger, Kevin J, Shvarts, Vladimir, Su, Yuan, Strain, Doug, Szalay, Marco, Trevithick, Matthew D, Villalonga, Benjamin, White, Theodore, Yao, Z Jamie, Yeh, Ping, Yoo, Juhwan, Zalcman, Adam, Neven, Hartmut, Boixo, Sergio, Smelyanskiy, Vadim, Megrant, Anthony, Kelly, Julian, and Chen, Yu
Subjects: Cold Temperature, Phase Transition, Thermodynamics, General Science & Technology
Abstract: Quantum many-body systems display rich phase structure in their low-temperature equilibrium states1. However, much of nature is not in thermal equilibrium. Remarkably, it was recently predicted that out-of-equilibrium systems can exhibit novel dynamical phases2-8 that may otherwise be forbidden by equilibrium thermodynamics, a paradigmatic example being the discrete time crystal (DTC)7,9-15. Concretely, dynamical phases can be defined in periodically driven many-body-localized (MBL) systems via the concept of eigenstate order7,16,17. In eigenstate-ordered MBL phases, the entire many-body spectrum exhibits quantum correlations and long-range order, with characteristic signatures in late-time dynamics from all initial states. It is, however, challenging to experimentally distinguish such stable phases from transient phenomena, or from regimes in which the dynamics of a few select states can mask typical behaviour. Here we implement tunable controlled-phase (CPHASE) gates on an array of superconducting qubits to experimentally observe an MBL-DTC and demonstrate its characteristic spatiotemporal response for generic initial states7,9,10. Our work employs a time-reversal protocol to quantify the impact of external decoherence, and leverages quantum typicality to circumvent the exponential cost of densely sampling the eigenspectrum. Furthermore, we locate the phase transition out of the DTC with an experimental finite-size analysis. These results establish a scalable approach to studying non-equilibrium phases of matter on quantum processors.
Published: 2022

21. Exponential suppression of bit or phase flip errors with repetitive error correction

Author: Chen, Zijun, Satzinger, Kevin J., Atalaya, Juan, Korotkov, Alexander N., Dunsworth, Andrew, Sank, Daniel, Quintana, Chris, McEwen, Matt, Barends, Rami, Klimov, Paul V., Hong, Sabrina, Jones, Cody, Petukhov, Andre, Kafri, Dvir, Demura, Sean, Burkett, Brian, Gidney, Craig, Fowler, Austin G., Putterman, Harald, Aleiner, Igor, Arute, Frank, Arya, Kunal, Babbush, Ryan, Bardin, Joseph C., Bengtsson, Andreas, Bourassa, Alexandre, Broughton, Michael, Buckley, Bob B., Buell, David A., Bushnell, Nicholas, Chiaro, Benjamin, Collins, Roberto, Courtney, William, Derk, Alan R., Eppens, Daniel, Erickson, Catherine, Farhi, Edward, Foxen, Brooks, Giustina, Marissa, Gross, Jonathan A., Harrigan, Matthew P., Harrington, Sean D., Hilton, Jeremy, Ho, Alan, Huang, Trent, Huggins, William J., Ioffe, L. B., Isakov, Sergei V., Jeffrey, Evan, Jiang, Zhang, Kechedzhi, Kostyantyn, Kim, Seon, Kostritsa, Fedor, Landhuis, David, Laptev, Pavel, Lucero, Erik, Martin, Orion, McClean, Jarrod R., McCourt, Trevor, Mi, Xiao, Miao, Kevin C., Mohseni, Masoud, Mruczkiewicz, Wojciech, Mutus, Josh, Naaman, Ofer, Neeley, Matthew, Neill, Charles, Newman, Michael, Niu, Murphy Yuezhen, O'Brien, Thomas E., Opremcak, Alex, Ostby, Eric, Pató, Bálint, Redd, Nicholas, Roushan, Pedram, Rubin, Nicholas C., Shvarts, Vladimir, Strain, Doug, Szalay, Marco, Trevithick, Matthew D., Villalonga, Benjamin, White, Theodore, Yao, Z. Jamie, Yeh, Ping, Zalcman, Adam, Neven, Hartmut, Boixo, Sergio, Smelyanskiy, Vadim, Chen, Yu, Megrant, Anthony, and Kelly, Julian
Subjects: Quantum Physics
Abstract: Realizing the potential of quantum computing will require achieving sufficiently low logical error rates. Many applications call for error rates in the $10^{-15}$ regime, but state-of-the-art quantum platforms typically have physical error rates near $10^{-3}$. Quantum error correction (QEC) promises to bridge this divide by distributing quantum logical information across many physical qubits so that errors can be detected and corrected. Logical errors are then exponentially suppressed as the number of physical qubits grows, provided that the physical error rates are below a certain threshold. QEC also requires that the errors are local and that performance is maintained over many rounds of error correction, two major outstanding experimental challenges. Here, we implement 1D repetition codes embedded in a 2D grid of superconducting qubits which demonstrate exponential suppression of bit or phase-flip errors, reducing logical error per round by more than $100\times$ when increasing the number of qubits from 5 to 21. Crucially, this error suppression is stable over 50 rounds of error correction. We also introduce a method for analyzing error correlations with high precision, and characterize the locality of errors in a device performing QEC for the first time. Finally, we perform error detection using a small 2D surface code logical qubit on the same device, and show that the results from both 1D and 2D codes agree with numerical simulations using a simple depolarizing error model. These findings demonstrate that superconducting qubits are on a viable path towards fault tolerant quantum computing.
Published: 2021
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22. Information Scrambling in Computationally Complex Quantum Circuits

Author: Mi, Xiao, Roushan, Pedram, Quintana, Chris, Mandra, Salvatore, Marshall, Jeffrey, Neill, Charles, Arute, Frank, Arya, Kunal, Atalaya, Juan, Babbush, Ryan, Bardin, Joseph C., Barends, Rami, Bengtsson, Andreas, Boixo, Sergio, Bourassa, Alexandre, Broughton, Michael, Buckley, Bob B., Buell, David A., Burkett, Brian, Bushnell, Nicholas, Chen, Zijun, Chiaro, Benjamin, Collins, Roberto, Courtney, William, Demura, Sean, Derk, Alan R., Dunsworth, Andrew, Eppens, Daniel, Erickson, Catherine, Farhi, Edward, Fowler, Austin G., Foxen, Brooks, Gidney, Craig, Giustina, Marissa, Gross, Jonathan A., Harrigan, Matthew P., Harrington, Sean D., Hilton, Jeremy, Ho, Alan, Hong, Sabrina, Huang, Trent, Huggins, William J., Ioffe, L. B., Isakov, Sergei V., Jeffrey, Evan, Jiang, Zhang, Jones, Cody, Kafri, Dvir, Kelly, Julian, Kim, Seon, Kitaev, Alexei, Klimov, Paul V., Korotkov, Alexander N., Kostritsa, Fedor, Landhuis, David, Laptev, Pavel, Lucero, Erik, Martin, Orion, McClean, Jarrod R., McCourt, Trevor, McEwen, Matt, Megrant, Anthony, Miao, Kevin C., Mohseni, Masoud, Mruczkiewicz, Wojciech, Mutus, Josh, Naaman, Ofer, Neeley, Matthew, Newman, Michael, Niu, Murphy Yuezhen, O'Brien, Thomas E., Opremcak, Alex, Ostby, Eric, Pato, Balint, Petukhov, Andre, Redd, Nicholas, Rubin, Nicholas C., Sank, Daniel, Satzinger, Kevin J., Shvarts, Vladimir, Strain, Doug, Szalay, Marco, Trevithick, Matthew D., Villalonga, Benjamin, White, Theodore, Yao, Z. Jamie, Yeh, Ping, Zalcman, Adam, Neven, Hartmut, Aleiner, Igor, Kechedzhi, Kostyantyn, Smelyanskiy, Vadim, and Chen, Yu
Subjects: Quantum Physics, Condensed Matter - Strongly Correlated Electrons, High Energy Physics - Theory
Abstract: Interaction in quantum systems can spread initially localized quantum information into the many degrees of freedom of the entire system. Understanding this process, known as quantum scrambling, is the key to resolving various conundrums in physics. Here, by measuring the time-dependent evolution and fluctuation of out-of-time-order correlators, we experimentally investigate the dynamics of quantum scrambling on a 53-qubit quantum processor. We engineer quantum circuits that distinguish the two mechanisms associated with quantum scrambling, operator spreading and operator entanglement, and experimentally observe their respective signatures. We show that while operator spreading is captured by an efficient classical model, operator entanglement requires exponentially scaled computational resources to simulate. These results open the path to studying complex and practically relevant physical observables with near-term quantum processors.
Published: 2021
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23. A fast and large bandwidth superconducting variable coupler

Author: Chang, Hung-Shen, Satzinger, Kevin J., Zhong, Youpeng, Bienfait, Audrey, Chou, Ming-Han, Conner, Christopher R., Dumur, Étienne, Grebel, Joel, Peairs, Gregory A., Povey, Rhys G., and Cleland, Andrew N.
Subjects: Physics - Applied Physics, Condensed Matter - Superconductivity, Quantum Physics
Abstract: Variable microwave-frequency couplers are highly useful components in classical communication systems, and likely will play an important role in quantum communication applications. Conventional semiconductor-based microwave couplers have been used with superconducting quantum circuits, enabling for example the in situ measurements of multiple devices via a common readout chain. However, the semiconducting elements are lossy, and furthermore dissipate energy when switched, making them unsuitable for cryogenic applications requiring rapid, repeated switching. Superconducting Josephson junction-based couplers can be designed for dissipation-free operation with fast switching and are easily integrated with superconducting quantum circuits. These enable on-chip, quantum-coherent routing of microwave photons, providing an appealing alternative to semiconductor switches. Here, we present and characterize a chip-based broadband microwave variable coupler, tunable over 4-8 GHz with over 1.5 GHz instantaneous bandwidth, based on the superconducting quantum interference device (SQUID) with two parallel Josephson junctions. The coupler is dissipation-free, features large on-off ratios in excess of 40 dB, and the coupling can be changed in about 10 ns. The simple design presented here can be readily integrated with superconducting qubit circuits, and can be easily generalized to realize a four- or more port device., Comment: 11 pages, 8 figures
Published: 2020
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24. Observation of separated dynamics of charge and spin in the Fermi-Hubbard model

Author: Arute, Frank, Arya, Kunal, Babbush, Ryan, Bacon, Dave, Bardin, Joseph C., Barends, Rami, Bengtsson, Andreas, Boixo, Sergio, Broughton, Michael, Buckley, Bob B., Buell, David A., Burkett, Brian, Bushnell, Nicholas, Chen, Yu, Chen, Zijun, Chen, Yu-An, Chiaro, Ben, Collins, Roberto, Cotton, Stephen J., Courtney, William, Demura, Sean, Derk, Alan, Dunsworth, Andrew, Eppens, Daniel, Eckl, Thomas, Erickson, Catherine, Farhi, Edward, Fowler, Austin, Foxen, Brooks, Gidney, Craig, Giustina, Marissa, Graff, Rob, Gross, Jonathan A., Habegger, Steve, Harrigan, Matthew P., Ho, Alan, Hong, Sabrina, Huang, Trent, Huggins, William, Ioffe, Lev B., Isakov, Sergei V., Jeffrey, Evan, Jiang, Zhang, Jones, Cody, Kafri, Dvir, Kechedzhi, Kostyantyn, Kelly, Julian, Kim, Seon, Klimov, Paul V., Korotkov, Alexander N., Kostritsa, Fedor, Landhuis, David, Laptev, Pavel, Lindmark, Mike, Lucero, Erik, Marthaler, Michael, Martin, Orion, Martinis, John M., Marusczyk, Anika, McArdle, Sam, McClean, Jarrod R., McCourt, Trevor, McEwen, Matt, Megrant, Anthony, Mejuto-Zaera, Carlos, Mi, Xiao, Mohseni, Masoud, Mruczkiewicz, Wojciech, Mutus, Josh, Naaman, Ofer, Neeley, Matthew, Neill, Charles, Neven, Hartmut, Newman, Michael, Niu, Murphy Yuezhen, O'Brien, Thomas E., Ostby, Eric, Pató, Bálint, Petukhov, Andre, Putterman, Harald, Quintana, Chris, Reiner, Jan-Michael, Roushan, Pedram, Rubin, Nicholas C., Sank, Daniel, Satzinger, Kevin J., Smelyanskiy, Vadim, Strain, Doug, Sung, Kevin J., Schmitteckert, Peter, Szalay, Marco, Tubman, Norm M., Vainsencher, Amit, White, Theodore, Vogt, Nicolas, Yao, Z. Jamie, Yeh, Ping, Zalcman, Adam, and Zanker, Sebastian
Subjects: Quantum Physics
Abstract: Strongly correlated quantum systems give rise to many exotic physical phenomena, including high-temperature superconductivity. Simulating these systems on quantum computers may avoid the prohibitively high computational cost incurred in classical approaches. However, systematic errors and decoherence effects presented in current quantum devices make it difficult to achieve this. Here, we simulate the dynamics of the one-dimensional Fermi-Hubbard model using 16 qubits on a digital superconducting quantum processor. We observe separations in the spreading velocities of charge and spin densities in the highly excited regime, a regime that is beyond the conventional quasiparticle picture. To minimize systematic errors, we introduce an accurate gate calibration procedure that is fast enough to capture temporal drifts of the gate parameters. We also employ a sequence of error-mitigation techniques to reduce decoherence effects and residual systematic errors. These procedures allow us to simulate the time evolution of the model faithfully despite having over 600 two-qubit gates in our circuits. Our experiment charts a path to practical quantum simulation of strongly correlated phenomena using available quantum devices., Comment: 20 pages, 15 figures
Published: 2020

25. Remote entanglement via adiabatic passage using a tunably-dissipative quantum communication system

Author: Chang, Hung-Shen, Zhong, Youpeng, Bienfait, Audrey, Chou, Ming-Han, Conner, Christopher R., Dumur, Étienne, Grebel, Joel, Peairs, Gregory A., Povey, Rhys G., Satzinger, Kevin J., and Cleland, Andrew N.
Subjects: Quantum Physics
Abstract: Effective quantum communication between remote quantum nodes requires high fidelity quantum state transfer and remote entanglement generation. Recent experiments have demonstrated that microwave photons, as well as phonons, can be used to couple superconducting qubits, with a fidelity limited primarily by loss in the communication channel. Adiabatic protocols can overcome channel loss by transferring quantum states without populating the lossy communication channel. Here we present a unique superconducting quantum communication system, comprising two superconducting qubits connected by a 0.73 m-long communication channel. Significantly, we can introduce large tunable loss to the channel, allowing exploration of different entanglement protocols in the presence of dissipation. When set for minimum loss in the channel, we demonstrate an adiabatic quantum state transfer protocol that achieves 99% transfer efficiency as well as the deterministic generation of entangled Bell states with a fidelity of 96%, all without populating the intervening communication channel, and competitive with a qubit-resonant mode-qubit relay method. We also explore the performance of the adiabatic protocol in the presence of significant channel loss, and show that the adiabatic protocol protects against loss in the channel, achieving higher state transfer and entanglement fidelities than the relay method., Comment: 27 pages, 14 figures
Published: 2020
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26. Quantum erasure using entangled surface acoustic phonons

Author: Bienfait, Audrey, Zhong, Youpeng, Chang, Hung-Shen, Chou, Ming-Han, Conner, Christopher R., Dumur, Étienne, Grebel, Joel, Peairs, Gregory A., Povey, Rhys G., Satzinger, Kevin J., and Cleland, Andrew N.
Subjects: Quantum Physics, Condensed Matter - Mesoscale and Nanoscale Physics
Abstract: Using the deterministic, on-demand generation of two entangled phonons, we demonstrate a quantum eraser protocol in a phononic interferometer where the which-path information can be heralded during the interference process. Omitting the heralding step yields a clear interference pattern in the interfering half-quanta pathways; including the heralding step suppresses this pattern. If we erase the heralded information after the interference has been measured, the interference pattern is recovered, thereby implementing a delayed-choice quantum erasure. The test is implemented using a closed surface-acoustic-wave communication channel into which one superconducting qubit can emit itinerant phonons that the same or a second qubit can later re-capture. If the first qubit releases only half of a phonon, the system follows a superposition of paths during the phonon propagation: either an itinerant phonon is in the channel, or the first qubit remains in its excited state. These two paths are made to constructively or destructively interfere by changing the relative phase of the two intermediate states, resulting in a phase-dependent modulation of the first qubit's final state, following interaction with the half-phonon. A heralding mechanism is added to this construct, entangling a heralding phonon with the signalling phonon. The first qubit emits a phonon herald conditioned on the qubit being in its excited state, with no signaling phonon, and the second qubit catches this heralding phonon, storing which-path information which can either be read out, destroying the signaling phonon's self-interference, or erased., Comment: 16 pages, 8 figures
Published: 2020
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27. Quantum Approximate Optimization of Non-Planar Graph Problems on a Planar Superconducting Processor

Author: Harrigan, Matthew P., Sung, Kevin J., Neeley, Matthew, Satzinger, Kevin J., Arute, Frank, Arya, Kunal, Atalaya, Juan, Bardin, Joseph C., Barends, Rami, Boixo, Sergio, Broughton, Michael, Buckley, Bob B., Buell, David A., Burkett, Brian, Bushnell, Nicholas, Chen, Yu, Chen, Zijun, Chiaro, Ben, Collins, Roberto, Courtney, William, Demura, Sean, Dunsworth, Andrew, Eppens, Daniel, Fowler, Austin, Foxen, Brooks, Gidney, Craig, Giustina, Marissa, Graff, Rob, Habegger, Steve, Ho, Alan, Hong, Sabrina, Huang, Trent, Ioffe, L. B., Isakov, Sergei V., Jeffrey, Evan, Jiang, Zhang, Jones, Cody, Kafri, Dvir, Kechedzhi, Kostyantyn, Kelly, Julian, Kim, Seon, Klimov, Paul V., Korotkov, Alexander N., Kostritsa, Fedor, Landhuis, David, Laptev, Pavel, Lindmark, Mike, Leib, Martin, Martin, Orion, Martinis, John M., McClean, Jarrod R., McEwen, Matt, Megrant, Anthony, Mi, Xiao, Mohseni, Masoud, Mruczkiewicz, Wojciech, Mutus, Josh, Naaman, Ofer, Neill, Charles, Neukart, Florian, Niu, Murphy Yuezhen, O'Brien, Thomas E., O'Gorman, Bryan, Ostby, Eric, Petukhov, Andre, Putterman, Harald, Quintana, Chris, Roushan, Pedram, Rubin, Nicholas C., Sank, Daniel, Skolik, Andrea, Smelyanskiy, Vadim, Strain, Doug, Streif, Michael, Szalay, Marco, Vainsencher, Amit, White, Theodore, Yao, Z. Jamie, Yeh, Ping, Zalcman, Adam, Zhou, Leo, Neven, Hartmut, Bacon, Dave, Lucero, Erik, Farhi, Edward, and Babbush, Ryan
Subjects: Quantum Physics
Abstract: We demonstrate the application of the Google Sycamore superconducting qubit quantum processor to combinatorial optimization problems with the quantum approximate optimization algorithm (QAOA). Like past QAOA experiments, we study performance for problems defined on the (planar) connectivity graph of our hardware; however, we also apply the QAOA to the Sherrington-Kirkpatrick model and MaxCut, both high dimensional graph problems for which the QAOA requires significant compilation. Experimental scans of the QAOA energy landscape show good agreement with theory across even the largest instances studied (23 qubits) and we are able to perform variational optimization successfully. For problems defined on our hardware graph we obtain an approximation ratio that is independent of problem size and observe, for the first time, that performance increases with circuit depth. For problems requiring compilation, performance decreases with problem size but still provides an advantage over random guessing for circuits involving several thousand gates. This behavior highlights the challenge of using near-term quantum computers to optimize problems on graphs differing from hardware connectivity. As these graphs are more representative of real world instances, our results advocate for more emphasis on such problems in the developing tradition of using the QAOA as a holistic, device-level benchmark of quantum processors., Comment: 19 pages, 15 figures
Published: 2020
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28. Hartree-Fock on a superconducting qubit quantum computer

Author: Arute, Frank, Arya, Kunal, Babbush, Ryan, Bacon, Dave, Bardin, Joseph C., Barends, Rami, Boixo, Sergio, Broughton, Michael, Buckley, Bob B., Buell, David A., Burkett, Brian, Bushnell, Nicholas, Chen, Yu, Chen, Zijun, Chiaro, Benjamin, Collins, Roberto, Courtney, William, Demura, Sean, Dunsworth, Andrew, Eppens, Daniel, Farhi, Edward, Fowler, Austin, Foxen, Brooks, Gidney, Craig, Giustina, Marissa, Graff, Rob, Habegger, Steve, Harrigan, Matthew P., Ho, Alan, Hong, Sabrina, Huang, Trent, Huggins, William J., Ioffe, Lev, Isakov, Sergei V., Jeffrey, Evan, Jiang, Zhang, Jones, Cody, Kafri, Dvir, Kechedzhi, Kostyantyn, Kelly, Julian, Kim, Seon, Klimov, Paul V., Korotkov, Alexander, Kostritsa, Fedor, Landhuis, David, Laptev, Pavel, Lindmark, Mike, Lucero, Erik, Martin, Orion, Martinis, John M., McClean, Jarrod R., McEwen, Matt, Megrant, Anthony, Mi, Xiao, Mohseni, Masoud, Mruczkiewicz, Wojciech, Mutus, Josh, Naaman, Ofer, Neeley, Matthew, Neill, Charles, Neven, Hartmut, Niu, Murphy Yuezhen, O'Brien, Thomas E., Ostby, Eric, Petukhov, Andre, Putterman, Harald, Quintana, Chris, Roushan, Pedram, Rubin, Nicholas C., Sank, Daniel, Satzinger, Kevin J., Smelyanskiy, Vadim, Strain, Doug, Sung, Kevin J., Szalay, Marco, Takeshita, Tyler Y., Vainsencher, Amit, White, Theodore, Wiebe, Nathan, Yao, Z. Jamie, Yeh, Ping, and Zalcman, Adam
Subjects: Quantum Physics, Physics - Chemical Physics
Abstract: As the search continues for useful applications of noisy intermediate scale quantum devices, variational simulations of fermionic systems remain one of the most promising directions. Here, we perform a series of quantum simulations of chemistry the largest of which involved a dozen qubits, 78 two-qubit gates, and 114 one-qubit gates. We model the binding energy of ${\rm H}_6$, ${\rm H}_8$, ${\rm H}_{10}$ and ${\rm H}_{12}$ chains as well as the isomerization of diazene. We also demonstrate error-mitigation strategies based on $N$-representability which dramatically improve the effective fidelity of our experiments. Our parameterized ansatz circuits realize the Givens rotation approach to non-interacting fermion evolution, which we variationally optimize to prepare the Hartree-Fock wavefunction. This ubiquitous algorithmic primitive corresponds to a rotation of the orbital basis and is required by many proposals for correlated simulations of molecules and Hubbard models. Because non-interacting fermion evolutions are classically tractable to simulate, yet still generate highly entangled states over the computational basis, we use these experiments to benchmark the performance of our hardware while establishing a foundation for scaling up more complex correlated quantum simulations of chemistry., Comment: updated link to experiment code, new version containing expanded data sets and corrected figure label
Published: 2020
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29. Exponential suppression of bit or phase errors with cyclic error correction

Author: Chen, Zijun, Satzinger, Kevin J, Atalaya, Juan, Korotkov, Alexander N, Dunsworth, Andrew, Sank, Daniel, Quintana, Chris, McEwen, Matt, Barends, Rami, Klimov, Paul V, Hong, Sabrina, Jones, Cody, Petukhov, Andre, Kafri, Dvir, Demura, Sean, Burkett, Brian, Gidney, Craig, Fowler, Austin G, Paler, Alexandru, Putterman, Harald, Aleiner, Igor, Arute, Frank, Arya, Kunal, Babbush, Ryan, Bardin, Joseph C, Bengtsson, Andreas, Bourassa, Alexandre, Broughton, Michael, Buckley, Bob B, Buell, David A, Bushnell, Nicholas, Chiaro, Benjamin, Collins, Roberto, Courtney, William, Derk, Alan R, Eppens, Daniel, Erickson, Catherine, Farhi, Edward, Foxen, Brooks, Giustina, Marissa, Greene, Ami, Gross, Jonathan A, Harrigan, Matthew P, Harrington, Sean D, Hilton, Jeremy, Ho, Alan, Huang, Trent, Huggins, William J, Ioffe, LB, Isakov, Sergei V, Jeffrey, Evan, Jiang, Zhang, Kechedzhi, Kostyantyn, Kim, Seon, Kitaev, Alexei, Kostritsa, Fedor, Landhuis, David, Laptev, Pavel, Lucero, Erik, Martin, Orion, McClean, Jarrod R, McCourt, Trevor, Mi, Xiao, Miao, Kevin C, Mohseni, Masoud, Montazeri, Shirin, Mruczkiewicz, Wojciech, Mutus, Josh, Naaman, Ofer, Neeley, Matthew, Neill, Charles, Newman, Michael, Niu, Murphy Yuezhen, O'Brien, Thomas E, Opremcak, Alex, Ostby, Eric, Pato, Balint, Redd, Nicholas, Roushan, Pedram, Rubin, Nicholas C, Shvarts, Vladimir, Strain, Doug, Szalay, Marco, Trevithick, Matthew D, Villalonga, Benjamin, White, Theodore, Yao, Z Jamie, Yeh, Ping, Yoo, Juhwan, Zalcman, Adam, Neven, Hartmut, Boixo, Sergio, Smelyanskiy, Vadim, Chen, Yu, Megrant, Anthony, and Kelly, Julian
Subjects: Google Quantum AI, General Science & Technology
Abstract: Realizing the potential of quantum computing requires sufficiently low logical error rates1. Many applications call for error rates as low as 10-15 (refs. 2-9), but state-of-the-art quantum platforms typically have physical error rates near 10-3 (refs. 10-14). Quantum error correction15-17 promises to bridge this divide by distributing quantum logical information across many physical qubits in such a way that errors can be detected and corrected. Errors on the encoded logical qubit state can be exponentially suppressed as the number of physical qubits grows, provided that the physical error rates are below a certain threshold and stable over the course of a computation. Here we implement one-dimensional repetition codes embedded in a two-dimensional grid of superconducting qubits that demonstrate exponential suppression of bit-flip or phase-flip errors, reducing logical error per round more than 100-fold when increasing the number of qubits from 5 to 21. Crucially, this error suppression is stable over 50 rounds of error correction. We also introduce a method for analysing error correlations with high precision, allowing us to characterize error locality while performing quantum error correction. Finally, we perform error detection with a small logical qubit using the 2D surface code on the same device18,19 and show that the results from both one- and two-dimensional codes agree with numerical simulations that use a simple depolarizing error model. These experimental demonstrations provide a foundation for building a scalable fault-tolerant quantum computer with superconducting qubits.
Published: 2021

30. Supplementary information for 'Quantum supremacy using a programmable superconducting processor'

Author: Arute, Frank, Arya, Kunal, Babbush, Ryan, Bacon, Dave, Bardin, Joseph C., Barends, Rami, Biswas, Rupak, Boixo, Sergio, Brandao, Fernando G. S. L., Buell, David A., Burkett, Brian, Chen, Yu, Chen, Zijun, Chiaro, Ben, Collins, Roberto, Courtney, William, Dunsworth, Andrew, Farhi, Edward, Foxen, Brooks, Fowler, Austin, Gidney, Craig, Giustina, Marissa, Graff, Rob, Guerin, Keith, Habegger, Steve, Harrigan, Matthew P., Hartmann, Michael J., Ho, Alan, Hoffmann, Markus R., Huang, Trent, Humble, Travis S., Isakov, Sergei V., Jeffrey, Evan, Jiang, Zhang, Kafri, Dvir, Kechedzhi, Kostyantyn, Kelly, Julian, Klimov, Paul V., Knysh, Sergey, Korotkov, Alexander N., Kostritsa, Fedor, Landhuis, David, Lindmark, Mike, Lucero, Erik, Lyakh, Dmitry, Mandra, Salvatore, McClean, Jarrod R., McEwen, Matt, Megrant, Anthony, Mi, Xiao, Michielsen, Kristel, Mohseni, Masoud, Mutus, Josh, Naaman, Ofer, Neeley, Matthew, Neill, Charles, Niu, Murphy Yuezhen, Ostby, Eric, Petukhov, Andre, Platt, John C., Quintana, Chris, Rieffel, Eleanor G., Roushan, Pedram, Rubin, Nicholas C., Sank, Daniel, Satzinger, Kevin J., Smelyanskiy, Vadim, Sung, Kevin J., Trevithick, Matthew D., Vainsencher, Amit, Villalonga, Benjamin, White, Theodore, Yao, Z. Jamie, Yeh, Ping, Zalcman, Adam, Neven, Hartmut, and Martinis, John M.
Subjects: Quantum Physics
Abstract: This is an updated version of supplementary information to accompany "Quantum supremacy using a programmable superconducting processor", an article published in the October 24, 2019 issue of Nature. The main article is freely available at https://www.nature.com/articles/s41586-019-1666-5. Summary of changes since arXiv:1910.11333v1 (submitted 23 Oct 2019): added URL for qFlex source code; added Erratum section; added Figure S41 comparing statistical and total uncertainty for log and linear XEB; new References [1,65]; miscellaneous updates for clarity and style consistency; miscellaneous typographical and formatting corrections., Comment: 67 pages, 51 figures
Published: 2019
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31. Probing spin-phonon interactions in silicon carbide with Gaussian acoustics

Author: Whiteley, Samuel J., Wolfowicz, Gary, Anderson, Christopher P., Bourassa, Alexandre, Ma, He, Ye, Meng, Koolstra, Gerwin, Satzinger, Kevin J., Holt, Martin V., Heremans, F. Joseph, Cleland, Andrew N., Schuster, David I., Galli, Giulia, and Awschalom, David D.
Subjects: Quantum Physics, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Materials Science
Abstract: Hybrid spin-mechanical systems provide a platform for integrating quantum registers and transducers. Efficient creation and control of such systems require a comprehensive understanding of the individual spin and mechanical components as well as their mutual interactions. Point defects in silicon carbide (SiC) offer long-lived, optically addressable spin registers in a wafer-scale material with low acoustic losses, making them natural candidates for integration with high quality factor mechanical resonators. Here, we show Gaussian focusing of a surface acoustic wave in SiC, characterized by a novel stroboscopic X-ray diffraction imaging technique, which delivers direct, strain amplitude information at nanoscale spatial resolution. Using ab initio calculations, we provide a more complete picture of spin-strain coupling for various defects in SiC with C3v symmetry. This reveals the importance of shear for future device engineering and enhanced spin-mechanical coupling. We demonstrate all-optical detection of acoustic paramagnetic resonance without microwave magnetic fields, relevant to sensing applications. Finally, we show mechanically driven Autler-Townes splittings and magnetically forbidden Rabi oscillations. These results offer a basis for full strain control of three-level spin systems., Comment: 17 pages, 4 figures
Published: 2018
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32. Spin–phonon interactions in silicon carbide addressed by Gaussian acoustics

Author: Whiteley, Samuel J, Wolfowicz, Gary, Anderson, Christopher P, Bourassa, Alexandre, Ma, He, Ye, Meng, Koolstra, Gerwin, Satzinger, Kevin J, Holt, Martin V, Heremans, F Joseph, Cleland, Andrew N, Schuster, David I, Galli, Giulia, and Awschalom, David D
Subjects: Bioengineering, quant-ph, cond-mat.mes-hall, cond-mat.mtrl-sci, Mathematical Sciences, Physical Sciences, Fluids & Plasmas
Abstract: Hybrid spin–mechanical systems provide a platform for integrating quantum registers and transducers. Efficient creation and control of such systems require a comprehensive understanding of the individual spin and mechanical components as well as their mutual interactions. Point defects in silicon carbide (SiC) offer long-lived, optically addressable spin registers in a wafer-scale material with low acoustic losses, making them natural candidates for integration with high-quality-factor mechanical resonators. Here, we show Gaussian focusing of a surface acoustic wave in SiC, characterized using a stroboscopic X-ray diffraction imaging technique, which delivers direct, strain amplitude information at nanoscale spatial resolution. Using ab initio calculations, we provide a more complete picture of spin–strain coupling for various defects in SiC with C 3v symmetry. This reveals the importance of shear strain for future device engineering and enhanced spin–mechanical coupling. We demonstrate all-optical detection of acoustic paramagnetic resonance without microwave magnetic fields, relevant for sensing applications. Finally, we show mechanically driven Autler–Townes splittings and magnetically forbidden Rabi oscillations. These results offer a basis for full strain control of three-level spin systems.
Published: 2019

33. Optimizing quantum gates towards the scale of logical qubits

Author: Klimov, Paul V., primary, Bengtsson, Andreas, additional, Quintana, Chris, additional, Bourassa, Alexandre, additional, Hong, Sabrina, additional, Dunsworth, Andrew, additional, Satzinger, Kevin J., additional, Livingston, William P., additional, Sivak, Volodymyr, additional, Niu, Murphy Yuezhen, additional, Andersen, Trond I., additional, Zhang, Yaxing, additional, Chik, Desmond, additional, Chen, Zijun, additional, Neill, Charles, additional, Erickson, Catherine, additional, Grajales Dau, Alejandro, additional, Megrant, Anthony, additional, Roushan, Pedram, additional, Korotkov, Alexander N., additional, Kelly, Julian, additional, Smelyanskiy, Vadim, additional, Chen, Yu, additional, and Neven, Hartmut, additional
Published: 2024
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34. Learning to Decode the Surface Code with a Recurrent, Transformer-Based Neural Network

Author: Bausch, Johannes, Senior, Andrew W, Heras, Francisco J H, Edlich, Thomas, Davies, Alex, Newman, Michael, Jones, Cody, Satzinger, Kevin, Niu, Murphy Yuezhen, Blackwell, Sam, Holland, George, Kafri, Dvir, Atalaya, Juan, Gidney, Craig, Hassabis, Demis, Boixo, Sergio, Neven, Hartmut, Kohli, Pushmeet, Bausch, Johannes, Senior, Andrew W, Heras, Francisco J H, Edlich, Thomas, Davies, Alex, Newman, Michael, Jones, Cody, Satzinger, Kevin, Niu, Murphy Yuezhen, Blackwell, Sam, Holland, George, Kafri, Dvir, Atalaya, Juan, Gidney, Craig, Hassabis, Demis, Boixo, Sergio, Neven, Hartmut, and Kohli, Pushmeet
Abstract: Quantum error-correction is a prerequisite for reliable quantum computation. Towards this goal, we present a recurrent, transformer-based neural network which learns to decode the surface code, the leading quantum error-correction code. Our decoder outperforms state-of-the-art algorithmic decoders on real-world data from Google's Sycamore quantum processor for distance 3 and 5 surface codes. On distances up to 11, the decoder maintains its advantage on simulated data with realistic noise including cross-talk, leakage, and analog readout signals, and sustains its accuracy far beyond the 25 cycles it was trained on. Our work illustrates the ability of machine learning to go beyond human-designed algorithms by learning from data directly, highlighting machine learning as a strong contender for decoding in quantum computers.
Published: 2023

35. Quantum information phases in space-time: measurement-induced entanglement and teleportation on a noisy quantum processor

Author: Hoke, Jesse, primary, Ippoliti, Matteo, additional, Abanin, Dmitry, additional, Acharya, Rajeev, additional, Ansmann, Markus, additional, Arute, Frank, additional, Arya, Kunal, additional, Asfaw, Abraham, additional, Atalaya, Juan, additional, Babbush, Ryan, additional, Bardin, Joseph, additional, Bengtsson, Andreas, additional, Bortoli, Gina, additional, Bourassa, Alexandre, additional, Bovaird, Jenna, additional, Brill, Leon, additional, Broughton, Michael, additional, Buckley, Bob, additional, Buell, David, additional, Burger, Tim, additional, Burkett, Brian, additional, Bushnell, Nicholas, additional, Chen, Zijun, additional, Chiaro, Ben, additional, Chik, Desmond, additional, Chou, Charina, additional, Cogan, Josh, additional, Collins, Roberto, additional, Conner, Paul, additional, Courtney, William, additional, Crook, Alexander, additional, Curtin, Ben, additional, Dau, Alejandro Grajales, additional, Debroy, Dripto, additional, Barba, Alexander Del Toro, additional, Demura, Sean, additional, Paolo, Augustin Di, additional, Drozdov, Ilya, additional, Dunsworth, Andrew, additional, Eppens, Daniel, additional, Erickson, Catherine, additional, Faoro, Lara, additional, Farhi, Edward, additional, Fatemi, Reza, additional, Ferreira, Vinicius, additional, Burgos, Leslie Flores, additional, Forati, Ebrahim, additional, Fowler, Austin, additional, Foxen, Brooks, additional, Giang, William, additional, Gidney, Craig, additional, Gilboa, Dar, additional, Giustina, Marissa, additional, Gosula, Raja, additional, Gross, Jonathan, additional, Habegger, Steve, additional, Hamilton, Michael, additional, Hansen, Monica, additional, Harrigan, Matthew, additional, Harrington, Sean, additional, Heu, Paula, additional, Hoffmann, Markus, additional, Hong, Sabrina, additional, Huang, Trent, additional, Huff, Ashley, additional, Huggins, William, additional, Isakov, Sergei, additional, Iveland, Justin, additional, Jeffrey, E., additional, Jones, Cody, additional, Juhas, Pavol, additional, Kafri, Dvir, additional, Kechedzhi, Kostyantyn, additional, Khattar, Tanuj, additional, Khezri, Mostafa, additional, Kieferova, Marika, additional, Kim, Seon, additional, Kitaev, Alexei, additional, Klimov, Paul, additional, Klots, Andrey, additional, Korotkov, Alexander, additional, Kostritsa, Fedor, additional, Kreikebaum, John Mark, additional, Landhuis, David, additional, Laptev, Pavel, additional, Lau, Kim-Ming, additional, Laws, Lily, additional, Lee, Joonho, additional, Lee, Kenny, additional, Lensky, Yuri, additional, Lester, Brian, additional, Lill, Alexander, additional, Liu, Wayne, additional, Locharla, Aditya, additional, Malone, Fionn, additional, Martin, Orion, additional, McClean, Jarrod, additional, McEwen, Matt, additional, Miao, Kevin, additional, Mieszala, Amanda, additional, Montazeri, Shirin, additional, Morvan, Alexis, additional, Movassagh, Ramis, additional, Mruczkiewicz, Wojciech, additional, Neeley, Matthew, additional, Neill, Charles, additional, Nersisyan, Ani, additional, Newman, Michael, additional, Ng, Jiun How, additional, Nguyen, Anthony, additional, Nguyen, Murray, additional, Niu, Murphy, additional, O'Brien, Thomas, additional, Omonije, Seun, additional, Opremcak, Alex, additional, Petukhov, Andre, additional, Potter, Rebecca, additional, Pryadko, Leonid, additional, Quintana, Chris, additional, Rocque, Charles, additional, Rubin, Nicholas, additional, Saei, Negar, additional, Sank, Daniel, additional, Sankaragomathi, Kannan, additional, Satzinger, Kevin, additional, Schurkus, Henry, additional, Schuster, Christopher, additional, Shearn, Michael, additional, Shorter, Aaron, additional, Shutty, Noah, additional, Vladimir, Shvarts, additional, Skruzny, Jindra, additional, Smith, W., additional, Somma, Rolando, additional, Sterling, George, additional, Strain, Doug, additional, Szalay, Marco, additional, Torres, Alfredo, additional, Vidal, Guifre, additional, Villalonga, Benjamin, additional, Heidweiller, Catherine Vollgraff, additional, White, Theodore, additional, Woo, Bryan, additional, Xing, Cheng, additional, Yao, Z. Jamie, additional, Yeh, Ping, additional, Yoo, Juhwan, additional, Young, Grayson, additional, Zalcman, Adam, additional, Zhang, Yaxing, additional, Zhu, Ningfeng, additional, Zobrist, Nicholas, additional, Neven, Hartmut, additional, Bacon, Dave, additional, Boixo, Sergio, additional, Hilton, Jeremy, additional, Lucero, Erik, additional, Megrant, Anthony, additional, Kelly, Julian, additional, Chen, Yu, additional, Smelyanskiy, Vadim, additional, Mi, Xiao, additional, Khemani, Vedika, additional, and Roushan, Pedram, additional
Published: 2023
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36. Quantum information phases in space-time: measurement-induced entanglement and teleportation on a noisy quantum processor

Author: Hoke, Jesse C., Ippoliti, Matteo, Abanin, Dmitry, Acharya, Rajeev, Ansmann, Markus, Arute, Frank, Arya, Kunal, Asfaw, Abraham, Atalaya, Juan, Bardin, Joseph C., Bengtsson, Andreas, Bortoli, Gina, Bourassa, Alexandre, Bovaird, Jenna, Brill, Leon, Broughton, Michael, Buckley, Bob B., Buell, David A., Burger, Tim, Burkett, Brian, Bushnell, Nicholas, Chen, Zijun, Chiaro, Ben, Chik, Desmond, Chou, Charina, Cogan, Josh, Collins, Roberto, Conner, Paul, Courtney, William, Crook, Alexander L., Curtin, Ben, Dau, Alejandro Grajales, Debroy, Dripto M., Barba, Alexander Del Toro, Demura, Sean, Di Paolo, Augustin, Drozdov, Ilya K., Dunsworth, Andrew, Eppens, Daniel, Erickson, Catherine, Faoro, Lara, Farhi, Edward, Fatem, Reza, Ferreira, Vinicius S., Burgos, Leslie Flores, Forati, Ebrahim, Fowler, Austin G., Foxen, Brooks, Giang, William, Gidney, Craig, Gilboa, Dar, Giustina, Marissa, Gosula, Raja, Gross, Jonathan A., Habegger, Steve, Hamilton, Michael C., Hansen, Monica, Harrigan, Matthew P., Harrington, Sean D., Heu, Paula, Hoffmann, Markus R., Hong, Sabrina, Huang, Trent, Huff, Ashley, Huggins, William J., Isakov, Sergei V., Iveland, Justin, Jeffr, Evan, Jones, Cody, Juhas, Pavol, Kafri, Dvir, Kechedzhi, Kostyantyn, Khattar, Tanuj, Khezri, Mostafa, Kieferová, Mária, Kim, Seon, Kitaev, Alexei, Klimov, Paul V., Klots, Andrey R., Korotkov, Alexander N., Kostritsa, Fedor, Kreikebaum, John Mark, Landhuis, David, Laptev, Pavel, Lau, Kim-Ming, Laws, Lily, Lee, Joonho, Lee, Kenny W., Lensky, Yuri D., Lester, Brian J., Lill, Alexander T., Liu, Wayne, Locharla, Aditya, Malone, Fionn D., Martin, Orion, McClean, Jarrod R., McCourt, Trevor, McEwen, Matt, Miao, Kevin C., Mieszala, Amanda, Montazeri, Shirin, Morvan, Alexis, Movassagh, Ramis, Mruczkiewicz, Wojciech, Neeley, Matthew, Neill, Charles, Nersisyan, Ani, Newman, Michael, Ng, Jiun H., Nguyen, Anthony, Nguyen, Murray, Niu, Murphy Yuezhen, O'Brien, Tom E., Omonije, Seun, Opremcak, Alex, Petukhov, Andre, Potter, Rebecca, Pryadko, Leonid P., Quintana, Chris, Rocque, Charles, Rubin, Nicholas C., Sank, Negar Saei Daniel, Sankaragomathi, Kannan, Satzinger, Kevin J., Schurkus, Henry F., Schuster, Christopher, Shearn, Michael J., Shorter, Aaron, Shutty, Noah, Shvarts, Vlad, Skruzny, Jindra, Smith, W. Clarke, Sterling, Rolando D. Somma George, Strain, Douglas, Szalay, Marco, Torres, Alfredo, Vidal, Guifre, Villalonga, Benjamin, Heidweiller, Catherine Vollgraff, White, Ted, Woo, Bryan W. K., Xing, Cheng, Yao, Z. Jamie., Yeh, Ping, Yoo, Juhwan, Young, Grayson, Zalcman, Adam, Zhang, Yaxing, Zhu, Ningfeng, Zobrist, Nicholas, Neven, Harmut, Babbush, Ryan, Bacon, Dave, Boixo, Sergio, Hilton, Jeremy, Lucero, Erik, Megrant, Anthony, Kelly, Julian, Chen, Yu, Smelyanskiy, Vadim, Mi, Xiao, Khemani, Vedika, and Roushan, Pedram
Subjects: High Energy Physics - Theory, Quantum Physics, Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Theory (hep-th), FOS: Physical sciences, Quantum Physics (quant-ph), Condensed Matter - Statistical Mechanics
Abstract: Measurement has a special role in quantum theory: by collapsing the wavefunction it can enable phenomena such as teleportation and thereby alter the "arrow of time" that constrains unitary evolution. When integrated in many-body dynamics, measurements can lead to emergent patterns of quantum information in space-time that go beyond established paradigms for characterizing phases, either in or out of equilibrium. On present-day NISQ processors, the experimental realization of this physics is challenging due to noise, hardware limitations, and the stochastic nature of quantum measurement. Here we address each of these experimental challenges and investigate measurement-induced quantum information phases on up to 70 superconducting qubits. By leveraging the interchangeability of space and time, we use a duality mapping, to avoid mid-circuit measurement and access different manifestations of the underlying phases -- from entanglement scaling to measurement-induced teleportation -- in a unified way. We obtain finite-size signatures of a phase transition with a decoding protocol that correlates the experimental measurement record with classical simulation data. The phases display sharply different sensitivity to noise, which we exploit to turn an inherent hardware limitation into a useful diagnostic. Our work demonstrates an approach to realize measurement-induced physics at scales that are at the limits of current NISQ processors.
Published: 2023

37. Readout of a quantum processor with high dynamic range Josephson parametric amplifiers

Author: White, Theodore, primary, Opremcak, Alex, additional, Sterling, George, additional, Korotkov, Alexander, additional, Sank, Daniel, additional, Acharya, Rajeev, additional, Ansmann, Markus, additional, Arute, Frank, additional, Arya, Kunal, additional, Bardin, Joseph C., additional, Bengtsson, Andreas, additional, Bourassa, Alexandre, additional, Bovaird, Jenna, additional, Brill, Leon, additional, Buckley, Bob B., additional, Buell, David A., additional, Burger, Tim, additional, Burkett, Brian, additional, Bushnell, Nicholas, additional, Chen, Zijun, additional, Chiaro, Ben, additional, Cogan, Josh, additional, Collins, Roberto, additional, Crook, Alexander L., additional, Curtin, Ben, additional, Demura, Sean, additional, Dunsworth, Andrew, additional, Erickson, Catherine, additional, Fatemi, Reza, additional, Burgos, Leslie Flores, additional, Forati, Ebrahim, additional, Foxen, Brooks, additional, Giang, William, additional, Giustina, Marissa, additional, Grajales Dau, Alejandro, additional, Hamilton, Michael C., additional, Harrington, Sean D., additional, Hilton, Jeremy, additional, Hoffmann, Markus, additional, Hong, Sabrina, additional, Huang, Trent, additional, Huff, Ashley, additional, Iveland, Justin, additional, Jeffrey, Evan, additional, Kieferová, Mária, additional, Kim, Seon, additional, Klimov, Paul V., additional, Kostritsa, Fedor, additional, Kreikebaum, John Mark, additional, Landhuis, David, additional, Laptev, Pavel, additional, Laws, Lily, additional, Lee, Kenny, additional, Lester, Brian J., additional, Lill, Alexander, additional, Liu, Wayne, additional, Locharla, Aditya, additional, Lucero, Erik, additional, McCourt, Trevor, additional, McEwen, Matt, additional, Mi, Xiao, additional, Miao, Kevin C., additional, Montazeri, Shirin, additional, Morvan, Alexis, additional, Neeley, Matthew, additional, Neill, Charles, additional, Nersisyan, Ani, additional, Ng, Jiun How, additional, Nguyen, Anthony, additional, Nguyen, Murray, additional, Potter, Rebecca, additional, Quintana, Chris, additional, Roushan, Pedram, additional, Sankaragomathi, Kannan, additional, Satzinger, Kevin J., additional, Schuster, Christopher, additional, Shearn, Michael J., additional, Shorter, Aaron, additional, Shvarts, Vladimir, additional, Skruzny, Jindra, additional, Smith, W. Clarke, additional, Szalay, Marco, additional, Torres, Alfredo, additional, Woo, Bryan W. K., additional, Yao, Z. Jamie, additional, Yeh, Ping, additional, Yoo, Juhwan, additional, Young, Grayson, additional, Zhu, Ningfeng, additional, Zobrist, Nicholas, additional, Chen, Yu, additional, Megrant, Anthony, additional, Kelly, Julian, additional, and Naaman, Ofer, additional
Published: 2023
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38. Measurement-Induced State Transitions in a Superconducting Qubit: Within the Rotating Wave Approximation

Author: Khezri, Mostafa, Opremcak, Alex, Chen, Zijun, Bengtsson, Andreas, White, Theodore, Naaman, Ofer, Acharya, Rajeev, Anderson, Kyle, Ansmann, Markus, Arute, Frank, Arya, Kunal, Asfaw, Abraham, Bardin, Joseph C., Bourassa, Alexandre, Bovaird, Jenna, Brill, Leon, Buckley, Bob B., Buell, David A., Burger, Tim, Burkett, Brian, Bushnell, Nicholas, Campero, Juan, Chiaro, Ben, Collins, Roberto, Crook, Alexander L., Curtin, Ben, Demura, Sean, Dunsworth, Andrew, Erickson, Catherine, Fatemi, Reza, Ferreira, Vinicius S., Burgos, Leslie Flores, Forati, Ebrahim, Foxen, Brooks, Garcia, Gonzalo, Giang, William, Giustina, Marissa, Gosula, Raja, Dau, Alejandro Grajales, Hamilton, Michael C., Harrington, Sean D., Heu, Paula, Hilton, Jeremy, Hoffmann, Markus R., Hong, Sabrina, Huang, Trent, Huff, Ashley, Iveland, Justin, Jeffrey, Evan, Kelly, Julian, Kim, Seon, Klimov, Paul V., Kostritsa, Fedor, Kreikebaum, John Mark, Landhuis, David, Laptev, Pavel, Laws, Lily, Lee, Kenny, Lester, Brian J., Lill, Alexander T., Liu, Wayne, Locharla, Aditya, Lucero, Erik, Martin, Steven, McEwen, Matt, Megrant, Anthony, Mi, Xiao, Miao, Kevin C., Montazeri, Shirin, Morvan, Alexis, Neeley, Matthew, Neill, Charles, Nersisyan, Ani, Ng, Jiun How, Nguyen, Anthony, Nguyen, Murray, Potter, Rebecca, Quintana, Chris, Rocque, Charles, Roushan, Pedram, Sankaragomathi, Kannan, Satzinger, Kevin J., Schuster, Christopher, Shearn, Michael J., Shorter, Aaron, Shvarts, Vladimir, Skruzny, Jindra, Smith, W. Clarke, Sterling, George, Szalay, Marco, Thor, Douglas, Torres, Alfredo, Woo, Bryan W. K., Yao, Z. Jamie, Yeh, Ping, Yoo, Juhwan, Young, Grayson, Zhu, Ningfeng, Zobrist, Nicholas, Sank, Daniel, Korotkov, Alexander, Chen, Yu, and Smelyanskiy, Vadim
Subjects: Quantum Physics, FOS: Physical sciences, Quantum Physics (quant-ph)
Abstract: Superconducting qubits typically use a dispersive readout scheme, where a resonator is coupled to a qubit such that its frequency is qubit-state dependent. Measurement is performed by driving the resonator, where the transmitted resonator field yields information about the resonator frequency and thus the qubit state. Ideally, we could use arbitrarily strong resonator drives to achieve a target signal-to-noise ratio in the shortest possible time. However, experiments have shown that when the average resonator photon number exceeds a certain threshold, the qubit is excited out of its computational subspace, which we refer to as a measurement-induced state transition. These transitions degrade readout fidelity, and constitute leakage which precludes further operation of the qubit in, for example, error correction. Here we study these transitions using a transmon qubit by experimentally measuring their dependence on qubit frequency, average photon number, and qubit state, in the regime where the resonator frequency is lower than the qubit frequency. We observe signatures of resonant transitions between levels in the coupled qubit-resonator system that exhibit noisy behavior when measured repeatedly in time. We provide a semi-classical model of these transitions based on the rotating wave approximation and use it to predict the onset of state transitions in our experiments. Our results suggest the transmon is excited to levels near the top of its cosine potential following a state transition, where the charge dispersion of higher transmon levels explains the observed noisy behavior of state transitions. Moreover, occupation in these higher energy levels poses a major challenge for fast qubit reset.
Published: 2022

39. Quantum control of surface acoustic wave phonons

Author: Satzinger, Kevin Joseph
Subjects: Physics, Quantum physics, Acoustics, Hybrid, Mechanics, Piezoelectric, Quantum, Qubit
Abstract: Quantum behavior in a macroscopic mechanical resonator is of great scientific and technological interest, but it is a substantial experimental challenge to realize. In particular, surface acoustic waves have emerged in recent years as a likely platform for coupling disparate quantum systems together. In this thesis, we present a surface acoustic wave resonator strongly coupled to a superconducting qubit. We begin by describing simple experiments with surface acoustic waves. Next, we discuss the design of a qubit and tunable coupler circuit to maintain good qubit performance in the presence of a surface acoustic wave resonator on an incompatible substrate. We then explain how to bring together devices on separate chips in a simple, accessible flip-chip assembly. Finally, we put these elements together to establish quantum control of surface acoustic wave phonons. We demonstrate good qubit performance and strong, tunable coupling to the acoustic mode. We show ground state cooling of the surface acoustic wave resonator with probability at least 99.5%. Finally, we illustrate quantum superposition in the surface acoustic wave resonator, conducting Wigner tomography of a superposition |0⟩ + |1⟩, which we find has fidelity 0.945 ± 0.006.
Published: 2018

40. Purification-based quantum error mitigation of pair-correlated electron simulations

Author: O'Brien, Thomas, primary, Anselmetti, Gian-Luca, additional, Gkritsis, Fotios, additional, Elfving, Vincent, additional, Polla, Stefano, additional, Huggins, William, additional, Oumarou, Oumarou, additional, Kechedzhi, Kostyantyn, additional, Abanin, Dmitry, additional, Acharya, Rajeev, additional, Aleiner, Igor, additional, Allen, Richard, additional, Andersen, Trond, additional, Anderson, Kyle, additional, Ansmann, Markus, additional, Arute, Frank, additional, Arya, Kunal, additional, Asfaw, Abraham, additional, Atalaya, Juan, additional, Bacon, Dave, additional, Bardin, Joseph, additional, Bengtsson, Andreas, additional, Boixo, Sergio, additional, Bortoli, Gina, additional, Bourassa, Alexandre, additional, Bovaird, Jenna, additional, Brill, Leon, additional, Broughton, Michael, additional, Buckley, Bob, additional, Buell, David, additional, Burger, Tim, additional, Burkett, Brian, additional, Bushnell, Nicholas, additional, Campero, Juan, additional, Chen, Yu, additional, Chen, Zijun, additional, Chiaro, Ben, additional, Chik, Desmond, additional, Cogan, Josh, additional, Collins, Roberto, additional, Conner, Paul, additional, Courtney, William, additional, Crook, Alexander, additional, Curtin, Ben, additional, Debroy, Dripto, additional, Barba, Alexander Del Toro, additional, Demura, Sean, additional, Drozdov, Ilya, additional, Dunsworth, Andrew, additional, Eppens, Daniel, additional, Erickson, Catherine, additional, Faoro, Lara, additional, Farhi, Edward, additional, Fatemi, Reza, additional, Ferreira, Vinicius, additional, Burgos, Leslie Flores, additional, Forati, Ebrahim, additional, Fowler, Austin, additional, Foxen, Brooks, additional, Giang, William, additional, Gidney, Craig, additional, Gilboa, Dar, additional, Giustina, Marissa, additional, Gosula, Raja, additional, Dau, Alejandro Grajales, additional, Gross, Jonathan, additional, Habegger, Steve, additional, Hamilton, Michael, additional, Hansen, Monica, additional, Harrigan, Matthew, additional, Harrington, Sean, additional, Heu, Paula, additional, Hilton, Jeremy, additional, Hoffmann, Markus, additional, Hong, Sabrina, additional, Huang, Trent, additional, Huff, Ashley, additional, Ioffe, L. B., additional, Isakov, Sergei, additional, Iveland, Justin, additional, Jeffrey, E., additional, Jiang, Zhang, additional, Jones, Cody, additional, Juhas, Pavol, additional, Kafri, Dvir, additional, Kelly, Julian, additional, Khattar, Tanuj, additional, Khezri, Mostafa, additional, Kieferova, Marika, additional, Kim, Seon, additional, Klimov, Paul, additional, Klots, Andrey, additional, Korotkov, Alexander, additional, Kostritsa, Fedor, additional, Kreikebaum, John Mark, additional, Landhuis, David, additional, Laptev, Pavel, additional, Lau, Kim-Ming, additional, Laws, Lily, additional, Lee, Joonho, additional, Lee, Kenny, additional, Lester, Brian, additional, Lill, Alexander, additional, Liu, Wayne, additional, Livingston, William, additional, Locharla, Aditya, additional, Lucero, Erik, additional, Malone, Fionn, additional, Mandra, Salvatore, additional, Martin, Orion, additional, Martin, Steven, additional, McClean, Jarrod, additional, McCourt, Trevor, additional, McEwen, Matthew, additional, Megrant, Anthony, additional, Mi, Xiao, additional, Miao, Kevin, additional, Mieszala, Amanda, additional, Mohseni, Masoud, additional, Montazeri, Shirin, additional, Morvan, Alexis, additional, Movassagh, Ramis, additional, Mruczkiewicz, Wojciech, additional, Naaman, Ofer, additional, Neeley, Matthew, additional, Neill, Charles, additional, Nersisyan, Ani, additional, Neven, Hartmut, additional, Newman, Michael, additional, Ng, Jiun How, additional, Nguyen, Anthony, additional, Nguyen, Murray, additional, Niu, Murphy, additional, Omonije, Seun, additional, Opremcak, Alex, additional, Petukhov, Andre, additional, Potter, Rebecca, additional, Pryadko, Leonid, additional, Quintana, Chris, additional, Rocque, Charles, additional, Roushan, Pedram, additional, Saei, Negar, additional, Sank, Daniel, additional, Sankaragomathi, Kannan, additional, Satzinger, Kevin, additional, Schurkus, Henry, additional, Shearn, Michael, additional, Shorter, Aaron, additional, Shutty, Noah, additional, Vladimir, Shvarts, additional, Skruzny, Jindra, additional, Smelyanskiy, Vadim, additional, Smith, W. Clarke, additional, Somma, Rolando, additional, Sterling, George, additional, Strain, Doug, additional, Szalay, Marco, additional, Thor, Douglas, additional, Torres, Alfredo, additional, Vidal, Guifre, additional, Villalonga, Benjamin, additional, Heidweiller, Catherine Vollgraff, additional, White, Theodore, additional, Woo, Bryan, additional, Xing, Cheng, additional, Yao, Z. Jamie, additional, Yeh, Ping, additional, Yoo, Juhwan, additional, Young, Grayson, additional, Zalcman, Adam, additional, Zhang, Yaxing, additional, Zhu, Ningfeng, additional, Zobrist, Nicholas, additional, Gogolin, Christian, additional, Babbush, Ryan, additional, and Rubin, Nicholas, additional
Published: 2022
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41. Information scrambling in quantum circuits

Author: Mi, Xiao, primary, Roushan, Pedram, additional, Quintana, Chris, additional, Mandrà, Salvatore, additional, Marshall, Jeffrey, additional, Neill, Charles, additional, Arute, Frank, additional, Arya, Kunal, additional, Atalaya, Juan, additional, Babbush, Ryan, additional, Bardin, Joseph C., additional, Barends, Rami, additional, Basso, Joao, additional, Bengtsson, Andreas, additional, Boixo, Sergio, additional, Bourassa, Alexandre, additional, Broughton, Michael, additional, Buckley, Bob B., additional, Buell, David A., additional, Burkett, Brian, additional, Bushnell, Nicholas, additional, Chen, Zijun, additional, Chiaro, Benjamin, additional, Collins, Roberto, additional, Courtney, William, additional, Demura, Sean, additional, Derk, Alan R., additional, Dunsworth, Andrew, additional, Eppens, Daniel, additional, Erickson, Catherine, additional, Farhi, Edward, additional, Fowler, Austin G., additional, Foxen, Brooks, additional, Gidney, Craig, additional, Giustina, Marissa, additional, Gross, Jonathan A., additional, Harrigan, Matthew P., additional, Harrington, Sean D., additional, Hilton, Jeremy, additional, Ho, Alan, additional, Hong, Sabrina, additional, Huang, Trent, additional, Huggins, William J., additional, Ioffe, L. B., additional, Isakov, Sergei V., additional, Jeffrey, Evan, additional, Jiang, Zhang, additional, Jones, Cody, additional, Kafri, Dvir, additional, Kelly, Julian, additional, Kim, Seon, additional, Kitaev, Alexei, additional, Klimov, Paul V., additional, Korotkov, Alexander N., additional, Kostritsa, Fedor, additional, Landhuis, David, additional, Laptev, Pavel, additional, Lucero, Erik, additional, Martin, Orion, additional, McClean, Jarrod R., additional, McCourt, Trevor, additional, McEwen, Matt, additional, Megrant, Anthony, additional, Miao, Kevin C., additional, Mohseni, Masoud, additional, Montazeri, Shirin, additional, Mruczkiewicz, Wojciech, additional, Mutus, Josh, additional, Naaman, Ofer, additional, Neeley, Matthew, additional, Newman, Michael, additional, Niu, Murphy Yuezhen, additional, O’Brien, Thomas E., additional, Opremcak, Alex, additional, Ostby, Eric, additional, Pato, Balint, additional, Petukhov, Andre, additional, Redd, Nicholas, additional, Rubin, Nicholas C., additional, Sank, Daniel, additional, Satzinger, Kevin J., additional, Shvarts, Vladimir, additional, Strain, Doug, additional, Szalay, Marco, additional, Trevithick, Matthew D., additional, Villalonga, Benjamin, additional, White, Theodore, additional, Yao, Z. Jamie, additional, Yeh, Ping, additional, Zalcman, Adam, additional, Neven, Hartmut, additional, Aleiner, Igor, additional, Kechedzhi, Kostyantyn, additional, Smelyanskiy, Vadim, additional, and Chen, Yu, additional
Published: 2021
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42. Resolving catastrophic error bursts from cosmic rays in large arrays of superconducting qubits

Author: McEwen, Matt, primary, Faoro, Lara, additional, Arya, Kunal, additional, Dunsworth, Andrew, additional, Huang, Trent, additional, Kim, Seon, additional, Burkett, Brian, additional, Fowler, Austin, additional, Arute, Frank, additional, Bardin, Joseph C., additional, Bengtsson, Andreas, additional, Bilmes, Alexander, additional, Buckley, Bob B., additional, Bushnell, Nicholas, additional, Chen, Zijun, additional, Collins, Roberto, additional, Demura, Sean, additional, Derk, Alan R., additional, Erickson, Catherine, additional, Giustina, Marissa, additional, Harrington, Sean D., additional, Hong, Sabrina, additional, Jeffrey, Evan, additional, Kelly, Julian, additional, Klimov, Paul V., additional, Kostritsa, Fedor, additional, Laptev, Pavel, additional, Locharla, Aditya, additional, Mi, Xiao, additional, Miao, Kevin C., additional, Montazeri, Shirin, additional, Mutus, Josh, additional, Naaman, Ofer, additional, Neeley, Matthew, additional, Neill, Charles, additional, Opremcak, Alex, additional, Quintana, Chris, additional, Redd, Nicholas, additional, Roushan, Pedram, additional, Sank, Daniel, additional, Satzinger, Kevin J., additional, Shvarts, Vladimir, additional, White, Theodore, additional, Yao, Z. Jamie, additional, Yeh, Ping, additional, Yoo, Juhwan, additional, Chen, Yu, additional, Smelyanskiy, Vadim, additional, Martinis, John M., additional, Neven, Hartmut, additional, Megrant, Anthony, additional, Ioffe, Lev, additional, and Barends, Rami, additional
Published: 2021
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43. Time-crystalline eigenstate order on a quantum processor

Author: Mi, Xiao, primary, Ippoliti, Matteo, additional, Quintana, Chris, additional, Greene, Ami, additional, Chen, Zijun, additional, Gross, Jonathan, additional, Arute, Frank, additional, Arya, Kunal, additional, Atalaya, Juan, additional, Babbush, Ryan, additional, Bardin, Joseph C., additional, Basso, Joao, additional, Bengtsson, Andreas, additional, Bilmes, Alexander, additional, Bourassa, Alexandre, additional, Brill, Leon, additional, Broughton, Michael, additional, Buckley, Bob B., additional, Buell, David A., additional, Burkett, Brian, additional, Bushnell, Nicholas, additional, Chiaro, Benjamin, additional, Collins, Roberto, additional, Courtney, William, additional, Debroy, Dripto, additional, Demura, Sean, additional, Derk, Alan R., additional, Dunsworth, Andrew, additional, Eppens, Daniel, additional, Erickson, Catherine, additional, Farhi, Edward, additional, Fowler, Austin G., additional, Foxen, Brooks, additional, Gidney, Craig, additional, Giustina, Marissa, additional, Harrigan, Matthew P., additional, Harrington, Sean D., additional, Hilton, Jeremy, additional, Ho, Alan, additional, Hong, Sabrina, additional, Huang, Trent, additional, Huff, Ashley, additional, Huggins, William J., additional, Ioffe, L. B., additional, Isakov, Sergei V., additional, Iveland, Justin, additional, Jeffrey, Evan, additional, Jiang, Zhang, additional, Jones, Cody, additional, Kafri, Dvir, additional, Khattar, Tanuj, additional, Kim, Seon, additional, Kitaev, Alexei, additional, Klimov, Paul V., additional, Korotkov, Alexander N., additional, Kostritsa, Fedor, additional, Landhuis, David, additional, Laptev, Pavel, additional, Lee, Joonho, additional, Lee, Kenny, additional, Locharla, Aditya, additional, Lucero, Erik, additional, Martin, Orion, additional, McClean, Jarrod R., additional, McCourt, Trevor, additional, McEwen, Matt, additional, Miao, Kevin C., additional, Mohseni, Masoud, additional, Montazeri, Shirin, additional, Mruczkiewicz, Wojciech, additional, Naaman, Ofer, additional, Neeley, Matthew, additional, Neill, Charles, additional, Newman, Michael, additional, Niu, Murphy Yuezhen, additional, O’Brien, Thomas E., additional, Opremcak, Alex, additional, Ostby, Eric, additional, Pato, Balint, additional, Petukhov, Andre, additional, Rubin, Nicholas C., additional, Sank, Daniel, additional, Satzinger, Kevin J., additional, Shvarts, Vladimir, additional, Su, Yuan, additional, Strain, Doug, additional, Szalay, Marco, additional, Trevithick, Matthew D., additional, Villalonga, Benjamin, additional, White, Theodore, additional, Yao, Z. Jamie, additional, Yeh, Ping, additional, Yoo, Juhwan, additional, Zalcman, Adam, additional, Neven, Hartmut, additional, Boixo, Sergio, additional, Smelyanskiy, Vadim, additional, Megrant, Anthony, additional, Kelly, Julian, additional, Chen, Yu, additional, Sondhi, S. L., additional, Moessner, Roderich, additional, Kechedzhi, Kostyantyn, additional, Khemani, Vedika, additional, and Roushan, Pedram, additional
Published: 2021
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44. Information scrambling in quantum circuits

Author: Mi, Xiao, Roushan, Pedram, Quintana, Chris, Mandrà, Salvatore, Marshall, Jeffrey, Neill, Charles, Arute, Frank, Arya, Kunal, Atalaya, Juan, Babbush, Ryan, Bardin, Joseph C., Barends, Rami, Basso, Joao, Bengtsson, Andreas, Boixo, Sergio, Bourassa, Alexandre, Broughton, Michael, Buckley, Bob B., Buell, David A., Burkett, Brian, Bushnell, Nicholas, Chen, Zijun, Chiaro, Benjamin, Collins, Roberto, Courtney, William, Demura, Sean, Derk, Alan R., Dunsworth, Andrew, Eppens, Daniel, Erickson, Catherine, Farhi, Edward, Fowler, Austin G., Foxen, Brooks, Gidney, Craig, Giustina, Marissa, Gross, Jonathan A., Harrigan, Matthew P., Harrington, Sean D., Hilton, Jeremy, Ho, Alan, Hong, Sabrina, Huang, Trent, Huggins, William J., Ioffe, L. B., Isakov, Sergei V., Jeffrey, Evan, Jiang, Zhang, Jones, Cody, Kafri, Dvir, Kelly, Julian, Kim, Seon, Kitaev, Alexei, Klimov, Paul V., Korotkov, Alexander N., Kostritsa, Fedor, Landhuis, David, Laptev, Pavel, Lucero, Erik, Martin, Orion, McClean, Jarrod R., McCourt, Trevor, McEwen, Matt, Megrant, Anthony, Miao, Kevin C., Mohseni, Masoud, Montazeri, Shirin, Mruczkiewicz, Wojciech, Mutus, Josh, Naaman, Ofer, Neeley, Matthew, Newman, Michael, Niu, Murphy Yuezhen, O'Brien, Thomas E., Opremcak, Alex, Ostby, Eric, Pato, Balint, Petukhov, Andre, Redd, Nicholas, Rubin, Nicholas C., Sank, Daniel, Satzinger, Kevin J., Shvarts, Vladimir, Strain, Doug, Szalay, Marco, Trevithick, Matthew D., Villalonga, Benjamin, White, Theodore, Yao, Z. Jamie, Yeh, Ping, Zalcman, Adam, Neven, Hartmut, Aleiner, Igor, Kechedzhi, Kostyantyn, Smelyanskiy, Vadim, Chen, Yu, Mi, Xiao, Roushan, Pedram, Quintana, Chris, Mandrà, Salvatore, Marshall, Jeffrey, Neill, Charles, Arute, Frank, Arya, Kunal, Atalaya, Juan, Babbush, Ryan, Bardin, Joseph C., Barends, Rami, Basso, Joao, Bengtsson, Andreas, Boixo, Sergio, Bourassa, Alexandre, Broughton, Michael, Buckley, Bob B., Buell, David A., Burkett, Brian, Bushnell, Nicholas, Chen, Zijun, Chiaro, Benjamin, Collins, Roberto, Courtney, William, Demura, Sean, Derk, Alan R., Dunsworth, Andrew, Eppens, Daniel, Erickson, Catherine, Farhi, Edward, Fowler, Austin G., Foxen, Brooks, Gidney, Craig, Giustina, Marissa, Gross, Jonathan A., Harrigan, Matthew P., Harrington, Sean D., Hilton, Jeremy, Ho, Alan, Hong, Sabrina, Huang, Trent, Huggins, William J., Ioffe, L. B., Isakov, Sergei V., Jeffrey, Evan, Jiang, Zhang, Jones, Cody, Kafri, Dvir, Kelly, Julian, Kim, Seon, Kitaev, Alexei, Klimov, Paul V., Korotkov, Alexander N., Kostritsa, Fedor, Landhuis, David, Laptev, Pavel, Lucero, Erik, Martin, Orion, McClean, Jarrod R., McCourt, Trevor, McEwen, Matt, Megrant, Anthony, Miao, Kevin C., Mohseni, Masoud, Montazeri, Shirin, Mruczkiewicz, Wojciech, Mutus, Josh, Naaman, Ofer, Neeley, Matthew, Newman, Michael, Niu, Murphy Yuezhen, O'Brien, Thomas E., Opremcak, Alex, Ostby, Eric, Pato, Balint, Petukhov, Andre, Redd, Nicholas, Rubin, Nicholas C., Sank, Daniel, Satzinger, Kevin J., Shvarts, Vladimir, Strain, Doug, Szalay, Marco, Trevithick, Matthew D., Villalonga, Benjamin, White, Theodore, Yao, Z. Jamie, Yeh, Ping, Zalcman, Adam, Neven, Hartmut, Aleiner, Igor, Kechedzhi, Kostyantyn, Smelyanskiy, Vadim, and Chen, Yu
Abstract: Interactions in quantum systems can spread initially localized quantum information into the exponentially many degrees of freedom of the entire system. Understanding this process, known as quantum scrambling, is key to resolving several open questions in physics. Here, by measuring the time-dependent evolution and fluctuation of out-of-time-order correlators, we experimentally investigate the dynamics of quantum scrambling on a 53-qubit quantum processor. We engineer quantum circuits that distinguish operator spreading and operator entanglement, and experimentally observe their respective signatures. We show that whereas operator spreading is captured by an efficient classical model, operator entanglement in idealized circuits requires exponentially scaled computational resources to simulate. These results open the path to studying complex and practically relevant physical observables with near-term quantum processors.
Published: 2021

45. Overcoming leakage in quantum error correction

Author: Miao, Kevin C., McEwen, Matt, Atalaya, Juan, Kafri, Dvir, Pryadko, Leonid P., Bengtsson, Andreas, Opremcak, Alex, Satzinger, Kevin J., Chen, Zijun, Klimov, Paul V., Quintana, Chris, Acharya, Rajeev, Anderson, Kyle, Ansmann, Markus, Arute, Frank, Arya, Kunal, Asfaw, Abraham, Bardin, Joseph C., Bourassa, Alexandre, Bovaird, Jenna, Brill, Leon, Buckley, Bob B., Buell, David A., Burger, Tim, Burkett, Brian, Bushnell, Nicholas, Campero, Juan, Chiaro, Ben, Collins, Roberto, Conner, Paul, Crook, Alexander L., Curtin, Ben, Debroy, Dripto M., Demura, Sean, Dunsworth, Andrew, Erickson, Catherine, Fatemi, Reza, Ferreira, Vinicius S., Burgos, Leslie Flores, Forati, Ebrahim, Fowler, Austin G., Foxen, Brooks, Garcia, Gonzalo, Giang, William, Gidney, Craig, Giustina, Marissa, Gosula, Raja, Dau, Alejandro Grajales, Gross, Jonathan A., Hamilton, Michael C., Harrington, Sean D., Heu, Paula, Hilton, Jeremy, Hoffmann, Markus R., Hong, Sabrina, Huang, Trent, Huff, Ashley, Iveland, Justin, Jeffrey, Evan, Jiang, Zhang, Jones, Cody, Kelly, Julian, Kim, Seon, Kostritsa, Fedor, Kreikebaum, John Mark, Landhuis, David, Laptev, Pavel, Laws, Lily, Lee, Kenny, Lester, Brian J., Lill, Alexander T., Liu, Wayne, Locharla, Aditya, Lucero, Erik, Martin, Steven, Megrant, Anthony, Mi, Xiao, Montazeri, Shirin, Morvan, Alexis, Naaman, Ofer, Neeley, Matthew, Neill, Charles, Nersisyan, Ani, Newman, Michael, Ng, Jiun How, Nguyen, Anthony, Nguyen, Murray, Potter, Rebecca, Rocque, Charles, Roushan, Pedram, Sankaragomathi, Kannan, Schurkus, Henry F., Schuster, Christopher, Shearn, Michael J., Shorter, Aaron, Shutty, Noah, Shvarts, Vladimir, Skruzny, Jindra, Smith, W. Clarke, Sterling, George, Szalay, Marco, Thor, Douglas, Torres, Alfredo, White, Theodore, Woo, Bryan W. K., Yao, Z. Jamie, Yeh, Ping, Yoo, Juhwan, Young, Grayson, Zalcman, Adam, Zhu, Ningfeng, Zobrist, Nicholas, Neven, Hartmut, Smelyanskiy, Vadim, Petukhov, Andre, Korotkov, Alexander N., Sank, Daniel, and Chen, Yu
Abstract: The leakage of quantum information out of the two computational states of a qubit into other energy states represents a major challenge for quantum error correction. During the operation of an error-corrected algorithm, leakage builds over time and spreads through multi-qubit interactions. This leads to correlated errors that degrade the exponential suppression of the logical error with scale, thus challenging the feasibility of quantum error correction as a path towards fault-tolerant quantum computation. Here, we demonstrate a distance-3 surface code and distance-21 bit-flip code on a quantum processor for which leakage is removed from all qubits in each cycle. This shortens the lifetime of leakage and curtails its ability to spread and induce correlated errors. We report a tenfold reduction in the steady-state leakage population of the data qubits encoding the logical state and an average leakage population of less than 1 × 10−3throughout the entire device. Our leakage removal process efficiently returns the system back to the computational basis. Adding it to a code circuit would prevent leakage from inducing correlated error across cycles. With this demonstration that leakage can be contained, we have resolved a key challenge for practical quantum error correction at scale.
Published: 2023
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46. Design and Characterization of a 28-nm Bulk-CMOS Cryogenic Quantum Controller Dissipating Less Than 2 mW at 3 K

Author: Bardin, Joseph C., primary, White, Ted, additional, Giustina, Marissa, additional, Satzinger, Kevin J., additional, Arya, Kunal, additional, Roushan, Pedram, additional, Chiaro, Benjamin, additional, Kelly, Julian, additional, Chen, Zijun, additional, Burkett, Brian, additional, Chen, Yu, additional, Jeffrey, Evan, additional, Dunsworth, Andrew, additional, Fowler, Austin, additional, Foxen, Brooks, additional, Gidney, Craig, additional, Graff, Rob, additional, Klimov, Paul, additional, Mutus, Josh, additional, McEwen, Matthew J., additional, Neeley, Matthew, additional, Neill, Charles J., additional, Lucero, Erik, additional, Quintana, Chris, additional, Vainsencher, Amit, additional, Neven, Hartmut, additional, Martinis, John, additional, Huang, Trent, additional, Das, Sayan, additional, Sank, Daniel Thomas, additional, Naaman, Ofer, additional, Megrant, Anthony Edward, additional, and Barends, Rami, additional
Published: 2019
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47. Quantum supremacy using a programmable superconducting processor

Author: Arute, Frank, primary, Arya, Kunal, additional, Babbush, Ryan, additional, Bacon, Dave, additional, Bardin, Joseph C., additional, Barends, Rami, additional, Biswas, Rupak, additional, Boixo, Sergio, additional, Brandao, Fernando G. S. L., additional, Buell, David A., additional, Burkett, Brian, additional, Chen, Yu, additional, Chen, Zijun, additional, Chiaro, Ben, additional, Collins, Roberto, additional, Courtney, William, additional, Dunsworth, Andrew, additional, Farhi, Edward, additional, Foxen, Brooks, additional, Fowler, Austin, additional, Gidney, Craig, additional, Giustina, Marissa, additional, Graff, Rob, additional, Guerin, Keith, additional, Habegger, Steve, additional, Harrigan, Matthew P., additional, Hartmann, Michael J., additional, Ho, Alan, additional, Hoffmann, Markus, additional, Huang, Trent, additional, Humble, Travis S., additional, Isakov, Sergei V., additional, Jeffrey, Evan, additional, Jiang, Zhang, additional, Kafri, Dvir, additional, Kechedzhi, Kostyantyn, additional, Kelly, Julian, additional, Klimov, Paul V., additional, Knysh, Sergey, additional, Korotkov, Alexander, additional, Kostritsa, Fedor, additional, Landhuis, David, additional, Lindmark, Mike, additional, Lucero, Erik, additional, Lyakh, Dmitry, additional, Mandrà, Salvatore, additional, McClean, Jarrod R., additional, McEwen, Matthew, additional, Megrant, Anthony, additional, Mi, Xiao, additional, Michielsen, Kristel, additional, Mohseni, Masoud, additional, Mutus, Josh, additional, Naaman, Ofer, additional, Neeley, Matthew, additional, Neill, Charles, additional, Niu, Murphy Yuezhen, additional, Ostby, Eric, additional, Petukhov, Andre, additional, Platt, John C., additional, Quintana, Chris, additional, Rieffel, Eleanor G., additional, Roushan, Pedram, additional, Rubin, Nicholas C., additional, Sank, Daniel, additional, Satzinger, Kevin J., additional, Smelyanskiy, Vadim, additional, Sung, Kevin J., additional, Trevithick, Matthew D., additional, Vainsencher, Amit, additional, Villalonga, Benjamin, additional, White, Theodore, additional, Yao, Z. Jamie, additional, Yeh, Ping, additional, Zalcman, Adam, additional, Neven, Hartmut, additional, and Martinis, John M., additional
Published: 2019
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48. The importance of cantilever dynamics in the interpretation of Kelvin probe force microscopy.

Author: Satzinger, Kevin J., Brown, Keith A., and Westervelt, Robert M.
Subjects: *CANTILEVERS, *ELECTROSTATICS, *SIMULATION methods & models, *CAPACITANCE-voltage characteristics, *BENDING (Metalwork)
Abstract: A realistic interpretation of the measured contact potential difference (CPD) in Kelvin probe force microscopy (KPFM) is crucial in order to extract meaningful information about the sample. Central to this interpretation is a method to include contributions from the macroscopic cantilever arm, as well as the cone and sharp tip of a KPFM probe. Here, three models of the electrostatic interaction between a KPFM probe and a sample are tested through an electrostatic simulation and compared with experiment. In contrast with previous studies that treat the KPFM cantilever as a rigid object, we allow the cantilever to bend and rotate; accounting for cantilever bending provides the closest agreement between theory and experiment. We demonstrate that cantilever dynamics play a major role in CPD measurements and provide a simulation technique to explore this phenomenon. [ABSTRACT FROM AUTHOR]
Published: 2012
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49. Quantum approximate optimization of non-planar graph problems on a planar superconducting processor

Author: Harrigan, Matthew P., Sung, Kevin J., Neeley, Matthew, Satzinger, Kevin J., Arute, Frank, Arya, Kunal, Atalaya, Juan, Bardin, Joseph C., Barends, Rami, Boixo, Sergio, Broughton, Michael, Buckley, Bob B., Buell, David A., Burkett, Brian, Bushnell, Nicholas, Chen, Yu, Chen, Zijun, Chiaro, Ben, Collins, Roberto, Courtney, William, Demura, Sean, Dunsworth, Andrew, Eppens, Daniel, Fowler, Austin, Foxen, Brooks, Gidney, Craig, Giustina, Marissa, Graff, Rob, Habegger, Steve, Ho, Alan, Hong, Sabrina, Huang, Trent, Ioffe, L. B., Isakov, Sergei V., Jeffrey, Evan, Jiang, Zhang, Jones, Cody, Kafri, Dvir, Kechedzhi, Kostyantyn, Kelly, Julian, Kim, Seon, Klimov, Paul V., Korotkov, Alexander N., Kostritsa, Fedor, Landhuis, David, Laptev, Pavel, Lindmark, Mike, Leib, Martin, Martin, Orion, Martinis, John M., McClean, Jarrod R., McEwen, Matt, Megrant, Anthony, Mi, Xiao, Mohseni, Masoud, Mruczkiewicz, Wojciech, Mutus, Josh, Naaman, Ofer, Neill, Charles, Neukart, Florian, Niu, Murphy Yuezhen, O’Brien, Thomas E., O’Gorman, Bryan, Ostby, Eric, Petukhov, Andre, Putterman, Harald, Quintana, Chris, Roushan, Pedram, Rubin, Nicholas C., Sank, Daniel, Skolik, Andrea, Smelyanskiy, Vadim, Strain, Doug, Streif, Michael, Szalay, Marco, Vainsencher, Amit, White, Theodore, Yao, Z. Jamie, Yeh, Ping, Zalcman, Adam, Zhou, Leo, Neven, Hartmut, Bacon, Dave, Lucero, Erik, Farhi, Edward, and Babbush, Ryan
Abstract: Faster algorithms for combinatorial optimization could prove transformative for diverse areas such as logistics, finance and machine learning. Accordingly, the possibility of quantum enhanced optimization has driven much interest in quantum technologies. Here we demonstrate the application of the Google Sycamore superconducting qubit quantum processor to combinatorial optimization problems with the quantum approximate optimization algorithm (QAOA). Like past QAOA experiments, we study performance for problems defined on the planar connectivity graph native to our hardware; however, we also apply the QAOA to the Sherrington–Kirkpatrick model and MaxCut, non-native problems that require extensive compilation to implement. For hardware-native problems, which are classically efficient to solve on average, we obtain an approximation ratio that is independent of problem size and observe that performance increases with circuit depth. For problems requiring compilation, performance decreases with problem size. Circuits involving several thousand gates still present an advantage over random guessing but not over some efficient classical algorithms. Our results suggest that it will be challenging to scale near-term implementations of the QAOA for problems on non-native graphs. As these graphs are closer to real-world instances, we suggest more emphasis should be placed on such problems when using the QAOA to benchmark quantum processors.
Published: 2021
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50. High spatial resolution Kelvin probe force microscopy with coaxial probes

Author: Brown, Keith A, primary, Satzinger, Kevin J, additional, and Westervelt, Robert M, additional
Published: 2012
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