Author: "Locharla A" - Searchworks@Jio Institute Digital Library Search Results

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151 results on '"Locharla A"'

1. 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

2. 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

3. 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

4. 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

5. Phase transitions in random circuit sampling

Author: Morvan, A., Villalonga, B., Mi, X., Mandrà, S., Bengtsson, A., Klimov, P. V., Chen, Z., Hong, S., Erickson, C., Drozdov, I. K., Chau, J., Laun, G., Movassagh, R., Asfaw, A., Brandão, L. T. A. N., Peralta, R., Abanin, D., Acharya, R., Allen, R., Andersen, T. I., Anderson, K., Ansmann, M., Arute, F., Arya, K., Atalaya, J., Bardin, J. C., Bilmes, A., Bortoli, G., Bourassa, A., Bovaird, J., Brill, L., Broughton, M., Buckley, B. B., Buell, D. A., Burger, T., Burkett, B., Bushnell, N., Campero, J., Chang, H.-S., Chiaro, B., Chik, D., Chou, C., Cogan, J., Collins, R., Conner, P., Courtney, W., Crook, A. L., Curtin, B., Debroy, D. M., Barba, A. Del Toro, Demura, S., Paolo, A. Di, Dunsworth, A., Faoro, L., Farhi, E., Fatemi, R., Ferreira, V. S., Burgos, L. Flores, Forati, E., Fowler, A. G., Foxen, B., Garcia, G., Genois, É., Giang, W., Gidney, C., Gilboa, D., Giustina, M., Gosula, R., Dau, A. Grajales, Gross, J. A., Habegger, S., Hamilton, M. C., Hansen, M., Harrigan, M. P., Harrington, S. D., Heu, P., Hoffmann, M. R., Huang, T., Huff, A., Huggins, W. J., Ioffe, L. B., Isakov, S. V., Iveland, J., Jeffrey, E., Jiang, Z., Jones, C., Juhas, P., Kafri, D., Khattar, T., Khezri, M., Kieferová, M., Kim, S., Kitaev, A., Klots, A. R., Korotkov, A. N., Kostritsa, F., Kreikebaum, J. M., Landhuis, D., Laptev, P., Lau, K.-M., Laws, L., Lee, J., Lee, K. W., Lensky, Y. D., Lester, B. J., Lill, A. T., Liu, W., Livingston, W. P., Locharla, A., Malone, F. D., Martin, O., Martin, S., McClean, J. R., McEwen, M., Miao, K. C., Mieszala, A., Montazeri, S., Mruczkiewicz, W., Naaman, O., Neeley, M., Neill, C., Nersisyan, A., Newman, M., Ng, J. H., Nguyen, A., Nguyen, M., Niu, M. Yuezhen, O’Brien, T. E., Omonije, S., Opremcak, A., Petukhov, A., Potter, R., Pryadko, L. P., Quintana, C., Rhodes, D. M., Rocque, C., Rosenberg, E., Rubin, N. C., Saei, N., Sank, D., Sankaragomathi, K., Satzinger, K. J., Schurkus, H. F., Schuster, C., Shearn, M. J., Shorter, A., Shutty, N., Shvarts, V., Sivak, V., Skruzny, J., Smith, W. C., Somma, R. D., Sterling, G., Strain, D., Szalay, M., Thor, D., Torres, A., Vidal, G., Heidweiller, C. Vollgraff, White, T., Woo, B. W. K., Xing, C., Yao, Z. J., Yeh, P., Yoo, J., Young, G., Zalcman, A., Zhang, Y., Zhu, N., Zobrist, N., Rieffel, E. G., Biswas, R., Babbush, R., Bacon, D., Hilton, J., Lucero, E., Neven, H., Megrant, A., Kelly, J., Roushan, P., Aleiner, I., Smelyanskiy, V., Kechedzhi, K., Chen, Y., and Boixo, S.
Published: 2024
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6. 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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7. Stable Quantum-Correlated Many Body States through Engineered Dissipation

Author: Mi, X., Michailidis, A. A., Shabani, S., Miao, K. C., Klimov, P. V., Lloyd, J., Rosenberg, E., Acharya, R., Aleiner, I., Andersen, T. I., Ansmann, M., Arute, F., Arya, K., Asfaw, A., Atalaya, J., Bardin, J. C., Bengtsson, A., Bortoli, G., Bourassa, A., Bovaird, J., Brill, L., Broughton, M., Buckley, B. B., Buell, D. A., Burger, T., Burkett, B., Bushnell, N., Chen, Z., Chiaro, B., Chik, D., Chou, C., Cogan, J., Collins, R., Conner, P., Courtney, W., Crook, A. L., Curtin, B., Dau, A. G., Debroy, D. M., Barba, A. Del Toro, Demura, S., Di Paolo, A., Drozdov, I. K., Dunsworth, A., Erickson, C., Faoro, L., Farhi, E., Fatemi, R., Ferreira, V. S., Forati, L. F. Burgos E., Fowler, A. G., Foxen, B., Genois, E., Giang, W., Gidney, C., Gilboa, D., Giustina, M., Gosula, R., Gross, J. A., Habegger, S., Hamilton, M. C., Hansen, M., Harrigan, M. P., Harrington, S. D., Heu, P., Hoffmann, M. R., Hong, S., Huang, T., Huff, A., Huggins, W. J., Ioffe, L. B., Isakov, S. V., Iveland, J., Jeffrey, E., Jiang, Z., Jones, C., Juhas, P., Kafri, D., Kechedzhi, K., Khattar, T., Khezri, M., Kieferova, M., Kim, S., Kitaev, A., Klots, A. R., Korotkov, A. N., Kostritsa, F., Kreikebaum, J. M., Landhuis, D., Laptev, P., Lau, K. -M., Laws, L., Lee, J., Lee, K. W., Lensky, Y. D., Lester, B. J., Lill, A. T., Liu, W., Locharla, A., Malone, F. D., Martin, O., McClean, J. R., McEwen, M., Mieszala, A., Montazeri, S., Morvan, A., Movassagh, R., Mruczkiewicz, W., Neeley, M., Neill, C., Nersisyan, A., Newman, M., Ng, J. H., Nguyen, A., Nguyen, M., Niu, M. Y., OBrien, T. E., Opremcak, A., Petukhov, A., Potter, R., Pryadko, L. P., Quintana, C., Rocque, C., Rubin, N. C., Saei, N., Sank, D., Sankaragomathi, K., Satzinger, K. J., Schurkus, H. F., Schuster, C., Shearn, M. J., Shorter, A., Shutty, N., Shvarts, V., Skruzny, J., Smith, W. C., Somma, R., Sterling, G., Strain, D., Szalay, M., Torres, A., Vidal, G., Villalonga, B., Heidweiller, C. V., White, T., Woo, B. W. K., Xing, C., Yao, Z. J., Yeh, P., Yoo, J., Young, G., Zalcman, A., Zhang, Y., Zhu, N., Zobrist, N., Neven, H., Babbush, R., Bacon, D., Boixo, S., Hilton, J., Lucero, E., Megrant, A., Kelly, J., Chen, Y., Roushan, P., Smelyanskiy, V., and Abanin, D. A.
Subjects: Quantum Physics
Abstract: Engineered dissipative reservoirs have the potential to steer many-body quantum systems toward correlated steady states useful for quantum simulation of high-temperature superconductivity or quantum magnetism. Using up to 49 superconducting qubits, we prepared low-energy states of the transverse-field Ising model through coupling to dissipative auxiliary qubits. In one dimension, we observed long-range quantum correlations and a ground-state fidelity of 0.86 for 18 qubits at the critical point. In two dimensions, we found mutual information that extends beyond nearest neighbors. Lastly, by coupling the system to auxiliaries emulating reservoirs with different chemical potentials, we explored transport in the quantum Heisenberg model. Our results establish engineered dissipation as a scalable alternative to unitary evolution for preparing entangled many-body states on noisy quantum processors.
Published: 2023
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8. Phase transition in Random Circuit Sampling

Author: Morvan, A., Villalonga, B., Mi, X., Mandrà, S., Bengtsson, A., Klimov, P. V., Chen, Z., Hong, S., Erickson, C., Drozdov, I. K., Chau, J., Laun, G., Movassagh, R., Asfaw, A., Brandão, L. T. A. N., Peralta, R., Abanin, D., Acharya, R., Allen, R., Andersen, T. I., Anderson, K., Ansmann, M., Arute, F., Arya, K., Atalaya, J., Bardin, J. C., Bilmes, A., Bortoli, G., Bourassa, A., Bovaird, J., Brill, L., Broughton, M., Buckley, B. B., Buell, D. A., Burger, T., Burkett, B., Bushnell, N., Campero, J., Chang, H. S., Chiaro, B., Chik, D., Chou, C., Cogan, J., Collins, R., Conner, P., Courtney, W., Crook, A. L., Curtin, B., Debroy, D. M., Barba, A. Del Toro, Demura, S., Di Paolo, A., Dunsworth, A., Faoro, L., Farhi, E., Fatemi, R., Ferreira, V. S., Burgos, L. Flores, Forati, E., Fowler, A. G., Foxen, B., Garcia, G., Genois, E., Giang, W., Gidney, C., Gilboa, D., Giustina, M., Gosula, R., Dau, A. Grajales, Gross, J. A., Habegger, S., Hamilton, M. C., Hansen, M., Harrigan, M. P., Harrington, S. D., Heu, P., Hoffmann, M. R., Huang, T., Huff, A., Huggins, W. J., Ioffe, L. B., Isakov, S. V., Iveland, J., Jeffrey, E., Jiang, Z., Jones, C., Juhas, P., Kafri, D., Khattar, T., Khezri, M., Kieferová, M., Kim, S., Kitaev, A., Klots, A. R., Korotkov, A. N., Kostritsa, F., Kreikebaum, J. M., Landhuis, D., Laptev, P., Lau, K. -M., Laws, L., Lee, J., Lee, K. W., Lensky, Y. D., Lester, B. J., Lill, A. T., Liu, W., Livingston, W. P., Locharla, A., Malone, F. D., Martin, O., Martin, S., McClean, J. R., McEwen, M., Miao, K. C., Mieszala, A., Montazeri, S., Mruczkiewicz, W., Naaman, O., Neeley, M., Neill, C., Nersisyan, A., Newman, M., Ng, J. H., Nguyen, A., Nguyen, M., Niu, M. Yuezhen, O'Brien, T. E., Omonije, S., Opremcak, A., Petukhov, A., Potter, R., Pryadko, L. P., Quintana, C., Rhodes, D. M., Rosenberg, E., Rocque, C., Roushan, P., Rubin, N. C., Saei, N., Sank, D., Sankaragomathi, K., Satzinger, K. J., Schurkus, H. F., Schuster, C., Shearn, M. J., Shorter, A., Shutty, N., Shvarts, V., Sivak, V., Skruzny, J., Smith, W. C., Somma, R. D., Sterling, G., Strain, D., Szalay, M., Thor, D., Torres, A., Vidal, G., Heidweiller, C. Vollgraff, White, T., Woo, B. W. K., Xing, C., Yao, Z. J., Yeh, P., Yoo, J., Young, G., Zalcman, A., Zhang, Y., Zhu, N., Zobrist, N., Rieffel, E. G., Biswas, R., Babbush, R., Bacon, D., Hilton, J., Lucero, E., Neven, H., Megrant, A., Kelly, J., Aleiner, I., Smelyanskiy, V., Kechedzhi, K., Chen, Y., and Boixo, S.
Subjects: Quantum Physics
Abstract: Undesired coupling to the surrounding environment destroys long-range correlations on quantum processors and hinders the coherent evolution in the nominally available computational space. This incoherent noise is an outstanding challenge to fully leverage the computation power of near-term quantum processors. It has been shown that benchmarking Random Circuit Sampling (RCS) with Cross-Entropy Benchmarking (XEB) can provide a reliable estimate of the effective size of the Hilbert space coherently available. The extent to which the presence of noise can trivialize the outputs of a given quantum algorithm, i.e. making it spoofable by a classical computation, is an unanswered question. Here, by implementing an RCS algorithm we demonstrate experimentally that there are two phase transitions observable with XEB, which we explain theoretically with a statistical model. The first is a dynamical transition as a function of the number of cycles and is the continuation of the anti-concentration point in the noiseless case. The second is a quantum phase transition controlled by the error per cycle; to identify it analytically and experimentally, we create a weak link model which allows varying the strength of noise versus coherent evolution. Furthermore, by presenting an RCS experiment with 67 qubits at 32 cycles, we demonstrate that the computational cost of our experiment is beyond the capabilities of existing classical supercomputers, even when accounting for the inevitable presence of noise. Our experimental and theoretical work establishes the existence of transitions to a stable computationally complex phase that is reachable with current quantum processors.
Published: 2023

9. 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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10. 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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11. Purification-based quantum error mitigation of pair-correlated electron simulations

Author: O'Brien, T. E., Anselmetti, G., Gkritsis, F., Elfving, V. E., Polla, S., Huggins, W. J., Oumarou, O., Kechedzhi, K., Abanin, D., Acharya, R., Aleiner, I., Allen, R., Andersen, T. I., Anderson, K., Ansmann, M., Arute, F., Arya, K., Asfaw, A., Atalaya, J., Bacon, D., Bardin, J. C., Bengtsson, A., Boixo, S., Bortoli, G., Bourassa, A., Bovaird, J., Brill, L., Broughton, M., Buckley, B., Buell, D. A., Burger, T., Burkett, B., Bushnell, N., Campero, J., Chen, Y., Chen, Z., Chiaro, B., Chik, D., Cogan, J., Collins, R., Conner, P., Courtney, W., Crook, A. L., Curtin, B., Debroy, D. M., Demura, S., Drozdov, I., Dunsworth, A., Erickson, C., Faoro, L., Farhi, E., Fatemi, R., Ferreira, V. S., Burgos, L. Flores, Forati, E., Fowler, A. G., Foxen, B., Giang, W., Gidney, C., Gilboa, D., Giustina, M., Gosula, R., Dau, A. Grajales, Gross, J. A., Habegger, S., Hamilton, M. C., Hansen, M., Harrigan, M. P., Harrington, S. D., Heu, P., Hilton, J., Hoffmann, M. R., Hong, S., Huang, T., Huff, A., Ioffe, L. B., Isakov, S. V., Iveland, J., Jeffrey, E., Jiang, Z., Jones, C., Juhas, P., Kafri, D., Kelly, J., Khattar, T., Khezri, M., Kieferová, M., Kim, S., Klimov, P. V., Klots, A. R., Kothari, R., Korotkov, A. N., Kostritsa, F., Kreikebaum, J. M., Landhuis, D., Laptev, P., Lau, K., Laws, L., Lee, J., Lee, K., Lester, B. J., Lill, A. T., Liu, W., Livingston, W. P., Locharla, A., Lucero, E., Malone, F. D., Mandra, S., Martin, O., Martin, S., McClean, J. R., McCourt, T., McEwen, M., Megrant, A., Mi, X., Mieszala, A., Miao, K. C., Mohseni, M., Montazeri, S., Morvan, A., Movassagh, R., Mruczkiewicz, W., Naaman, O., Neeley, M., Neill, C., Nersisyan, A., Neven, H., Newman, M., Ng, J. H., Nguyen, A., Nguyen, M., Niu, M. Y., Omonije, S., Opremcak, A., Petukhov, A., Potter, R., Pryadko, L. P., Quintana, C., Rocque, C., Roushan, P., Saei, N., Sank, D., Sankaragomathi, K., Satzinger, K. J., Schurkus, H. F., Schuster, C., Shearn, M. J., Shorter, A., Shutty, N., Shvarts, V., Skruzny, J., Smelyanskiy, V., Smith, W. C., Somma, R., Sterling, G., Strain, D., Szalay, M., Thor, D., Torres, A., Vidal, G., Villalonga, B., Heidweiller, C. Vollgraff, White, T., Woo, B. W. K., Xing, C., Yao, Z. J., Yeh, P., Yoo, J., Young, G., Zalcman, A., Zhang, Y., Zhu, N., Zobrist, N., Gogolin, C., Babbush, R., and Rubin, N. C.
Subjects: Quantum Physics
Abstract: An important measure of the development of quantum computing platforms has been the simulation of increasingly complex physical systems. Prior to fault-tolerant quantum computing, robust error mitigation strategies are necessary to continue this growth. Here, we study physical simulation within the seniority-zero electron pairing subspace, which affords both a computational stepping stone to a fully correlated model, and an opportunity to validate recently introduced ``purification-based'' error-mitigation strategies. We compare the performance of error mitigation based on doubling quantum resources in time (echo verification) or in space (virtual distillation), on up to $20$ qubits of a superconducting qubit quantum processor. We observe a reduction of error by one to two orders of magnitude below less sophisticated techniques (e.g. post-selection); the gain from error mitigation is seen to increase with the system size. Employing these error mitigation strategies enables the implementation of the largest variational algorithm for a correlated chemistry system to-date. Extrapolating performance from these results allows us to estimate minimum requirements for a beyond-classical simulation of electronic structure. We find that, despite the impressive gains from purification-based error mitigation, significant hardware improvements will be required for classically intractable variational chemistry simulations., Comment: 10 pages, 13 page supplementary material, 12 figures. Experimental data available at https://doi.org/10.5281/zenodo.7225821
Published: 2022
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12. 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

13. 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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14. 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
Published: 2023
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15. Purification-based quantum error mitigation of pair-correlated electron simulations

Author: O’Brien, T. E., Anselmetti, G., Gkritsis, F., Elfving, V. E., Polla, S., Huggins, W. J., Oumarou, O., Kechedzhi, K., Abanin, D., Acharya, R., Aleiner, I., Allen, R., Andersen, T. I., Anderson, K., Ansmann, M., Arute, F., Arya, K., Asfaw, A., Atalaya, J., Bardin, J. C., Bengtsson, A., Bortoli, G., Bourassa, A., Bovaird, J., Brill, L., Broughton, M., Buckley, B., Buell, D. A., Burger, T., Burkett, B., Bushnell, N., Campero, J., Chen, Z., Chiaro, B., Chik, D., Cogan, J., Collins, R., Conner, P., Courtney, W., Crook, A. L., Curtin, B., Debroy, D. M., Demura, S., Drozdov, I., Dunsworth, A., Erickson, C., Faoro, L., Farhi, E., Fatemi, R., Ferreira, V. S., Flores Burgos, L., Forati, E., Fowler, A. G., Foxen, B., Giang, W., Gidney, C., Gilboa, D., Giustina, M., Gosula, R., Grajales Dau, A., Gross, J. A., Habegger, S., Hamilton, M. C., Hansen, M., Harrigan, M. P., Harrington, S. D., Heu, P., Hoffmann, M. R., Hong, S., Huang, T., Huff, A., Ioffe, L. B., Isakov, S. V., Iveland, J., Jeffrey, E., Jiang, Z., Jones, C., Juhas, P., Kafri, D., Khattar, T., Khezri, M., Kieferová, M., Kim, S., Klimov, P. V., Klots, A. R., Korotkov, A. N., Kostritsa, F., Kreikebaum, J. M., Landhuis, D., Laptev, P., Lau, K.-M., Laws, L., Lee, J., Lee, K., Lester, B. J., Lill, A. T., Liu, W., Livingston, W. P., Locharla, A., Malone, F. D., Mandrà, S., Martin, O., Martin, S., McClean, J. R., McCourt, T., McEwen, M., Mi, X., Mieszala, A., Miao, K. C., Mohseni, M., Montazeri, S., Morvan, A., Movassagh, R., Mruczkiewicz, W., Naaman, O., Neeley, M., Neill, C., Nersisyan, A., Newman, M., Ng, J. H., Nguyen, A., Nguyen, M., Niu, M. Y., Omonije, S., Opremcak, A., Petukhov, A., Potter, R., Pryadko, L. P., Quintana, C., Rocque, C., Roushan, P., Saei, N., Sank, D., Sankaragomathi, K., Satzinger, K. J., Schurkus, H. F., Schuster, C., Shearn, M. J., Shorter, A., Shutty, N., Shvarts, V., Skruzny, J., Smith, W. C., Somma, R. D., Sterling, G., Strain, D., Szalay, M., Thor, D., Torres, A., Vidal, G., Villalonga, B., Vollgraff Heidweiller, C., White, T., Woo, B. W. K., Xing, C., Yao, Z. J., Yeh, P., Yoo, J., Young, G., Zalcman, A., Zhang, Y., Zhu, N., Zobrist, N., Bacon, D., Boixo, S., Chen, Y., Hilton, J., Kelly, J., Lucero, E., Megrant, A., Neven, H., Smelyanskiy, V., Gogolin, C., Babbush, R., and Rubin, N. C.
Published: 2023
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16. 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

17. 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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18. Formation of robust bound states of interacting microwave photons

Author: Morvan, A, Andersen, TI, Mi, X, Neill, C, Petukhov, A, Kechedzhi, K, Abanin, DA, Michailidis, A, Acharya, R, Arute, F, Arya, K, Asfaw, A, Atalaya, J, Bardin, JC, Basso, J, Bengtsson, A, Bortoli, G, Bourassa, A, Bovaird, J, Brill, L, Broughton, M, Buckley, BB, Buell, DA, Burger, T, Burkett, B, Bushnell, N, Chen, Z, Chiaro, B, Collins, R, Conner, P, Courtney, W, Crook, AL, Curtin, B, Debroy, DM, Del Toro Barba, A, Demura, S, Dunsworth, A, Eppens, D, Erickson, C, Faoro, L, Farhi, E, Fatemi, R, Flores Burgos, L, Forati, E, Fowler, AG, Foxen, B, Giang, W, Gidney, C, Gilboa, D, Giustina, M, Grajales Dau, A, Gross, JA, Habegger, S, Hamilton, MC, Harrigan, MP, Harrington, SD, Hoffmann, M, Hong, S, Huang, T, Huff, A, Huggins, WJ, Isakov, SV, Iveland, J, Jeffrey, E, Jiang, Z, Jones, C, Juhas, P, Kafri, D, Khattar, T, Khezri, M, Kieferová, M, Kim, S, Kitaev, AY, Klimov, PV, Klots, AR, Korotkov, AN, Kostritsa, F, Kreikebaum, JM, Landhuis, D, Laptev, P, Lau, K-M, Laws, L, Lee, J, Lee, KW, Lester, BJ, Lill, AT, Liu, W, Locharla, A, Malone, F, Martin, O, McClean, JR, McEwen, M, Meurer Costa, B, Miao, KC, Mohseni, M, Montazeri, S, Mount, E, Mruczkiewicz, W, Naaman, O, and Neeley, M
Subjects: Quantum Physics, Physical Sciences, Photons, Microwaves, Electrons, Fees and Charges, Reproduction, General Science & Technology
Abstract: Systems of correlated particles appear in many fields of modern science and represent some of the most intractable computational problems 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 particles1. The lack of general solutions for the three-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 multiparticle bound states2-9. Here we develop a high-fidelity parameterizable fSim gate and implement the periodic quantum circuit of the spin-½ XXZ model in a ring of 24 superconducting qubits. We study the propagation of these excitations and observe their bound nature for up to five 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 idea 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.
Published: 2022

19. 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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20. LILLIPUT: A Lightweight Low-Latency Lookup-Table Based Decoder for Near-term Quantum Error Correction

Author: Das, Poulami, Locharla, Aditya, and Jones, Cody
Subjects: Quantum Physics, Computer Science - Hardware Architecture
Abstract: The error rates of quantum devices are orders of magnitude higher than what is needed to run most quantum applications. To close this gap, Quantum Error Correction (QEC) encodes logical qubits and distributes information using several physical qubits. By periodically executing a syndrome extraction circuit on the logical qubits, information about errors (called syndrome) is extracted while running programs. A decoder uses these syndromes to identify and correct errors in real time, which is required to use feedback implemented in quantum algorithms. Unfortunately, software decoders are slow and hardware decoders are fast but less accurate. Thus, almost all QEC studies so far have relied on offline decoding. To enable real-time decoding in near-term QEC, we propose LILLIPUT-- a Lightweight Low Latency Look-Up Table decoder. LILLIPUT consists of two parts-- First, it translates syndromes into error detection events that index into a Look-Up Table (LUT) whose entry provides the error information in real-time. Second, it programs the LUTs with error assignments for all possible error events by running a software decoder offline. LILLIPUT tolerates an error on any operation in the quantum hardware, including gates and measurement, and the number of tolerated errors grows with the size of the code. It needs <7% logic on off-the-shelf FPGAs that allows it to be easily integrated alongside the control and readout circuits in existing systems. LILLIPUT incurs a latency of few nanoseconds and enables real-time decoding. We also propose Compressed LUTs (CLUTs) to reduce the memory needed by LILLIPUT. By exploiting the fact that not all error events are equally likely and only storing data for the most probable error events, CLUTs reduce the memory needed by up-to 107x (from 148 MB to 1.38 MB) without degrading accuracy., Comment: 13 pages,17 Figures, 6 Tables
Published: 2021

21. 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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22. 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

23. 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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24. Realizing topologically ordered states on a quantum processor

Author: Satzinger, K. J., Liu, Y., Smith, A., Knapp, C., Newman, M., Jones, C., Chen, Z., Quintana, C., Mi, X., Dunsworth, A., Gidney, C., Aleiner, I., Arute, F., Arya, K., Atalaya, J., Babbush, R., Bardin, J. C., Barends, R., Basso, J., Bengtsson, A., Bilmes, A., Broughton, M., Buckley, B. B., Buell, D. A., Burkett, B., Bushnell, N., Chiaro, B., Collins, R., Courtney, W., Demura, S., Derk, A. R., Eppens, D., Erickson, C., Farhi, E., Foaro, L., Fowler, A. G., Foxen, B., Giustina, M., Greene, A., Gross, J. A., Harrigan, M. P., Harrington, S. D., Hilton, J., Hong, S., Huang, T., Huggins, W. J., Ioffe, L. B., Isakov, S. V., Jeffrey, E., Jiang, Z., Kafri, D., Kechedzhi, K., Khattar, T., Kim, S., Klimov, P. V., Korotkov, A. N., Kostritsa, F., Landhuis, D., Laptev, P., Locharla, A., Lucero, E., Martin, O., McClean, J. R., McEwen, M., Miao, K. C., Mohseni, M., Montazeri, S., Mruczkiewicz, W., Mutus, J., Naaman, O., Neeley, M., Neill, C., Niu, M. Y., O'Brien, T. E., Opremcak, A., Pató, B., Petukhov, A., Rubin, N. C., Sank, D., Shvarts, V., Strain, D., Szalay, M., Villalonga, B., White, T. C., Yao, Z., Yeh, P., Yoo, J., Zalcman, A., Neven, H., Boixo, S., Megrant, A., Chen, Y., Kelly, J., Smelyanskiy, V., Kitaev, A., Knap, M., Pollmann, F., and Roushan, P.
Subjects: Quantum Physics, Condensed Matter - Strongly Correlated Electrons
Abstract: The discovery of topological order has revolutionized the understanding of quantum matter in modern physics and provided the theoretical foundation for many quantum error correcting codes. Realizing topologically ordered states has proven to be extremely challenging in both condensed matter and synthetic quantum systems. Here, we prepare the ground state of the toric code Hamiltonian using an efficient quantum circuit on a superconducting quantum processor. We measure a topological entanglement entropy near the expected value of $\ln2$, and simulate anyon interferometry to extract the braiding statistics of the emergent excitations. Furthermore, we investigate key aspects of the surface code, including logical state injection and the decay of the non-local order parameter. Our results demonstrate the potential for quantum processors to provide key insights into topological quantum matter and quantum error correction., Comment: 6 pages 4 figures, plus supplementary materials
Published: 2021
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25. A Robust Deep Learning Techniques for Alzheimer’s Prediction

Author: Locharla, Jayesh, Kolanuvada, Haswanth, Ashrith, Kona Venkata Sai, Suchitra, S., Kacprzyk, Janusz, Series Editor, Gomide, Fernando, Advisory Editor, Kaynak, Okyay, Advisory Editor, Liu, Derong, Advisory Editor, Pedrycz, Witold, Advisory Editor, Polycarpou, Marios M., Advisory Editor, Rudas, Imre J., Advisory Editor, Wang, Jun, Advisory Editor, Tanwar, Sudeep, editor, Wierzchon, Slawomir T., editor, Singh, Pradeep Kumar, editor, Ganzha, Maria, editor, and Epiphaniou, Gregory, editor
Published: 2023
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26. LILLIPUT: a lightweight low-latency lookup-table decoder for near-term Quantum error correction.

Author: Poulami Das 0005, Aditya Locharla, and Cody Jones
Published: 2022
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27. Compression Techniques for Low Power Hardware Accelerator Design: Case Studies

Author: Locharla, Govinda Rao, Revathi, Pogiri, Rao, M. V. Nageswara, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Hirche, Sandra, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Möller, Sebastian, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Oneto, Luca, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zamboni, Walter, Series Editor, Zhang, Junjie James, Series Editor, Kumar Jain, Pradip, editor, Nath Singh, Yatindra, editor, Gollapalli, Ravi Paul, editor, and Singh, S. P., editor
Published: 2022
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28. 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
Published: 2022
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29. EEG-based deep learning neural net for apnea detection

Author: Locharla, Govinda Rao, primary, Pogiri, Revathi, additional, and Allam, Jaya Prakash, additional
Published: 2022
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30. Contributors

Author: Allam, Jaya Prakash, primary, Aslani, Mohammad Reza, additional, Bajaj, Varun, additional, Behara, Chinmaya, additional, Daftari, Charmi, additional, Demir, Fatih, additional, Farahi, Morteza, additional, Gautam, Anil Kumar, additional, Ghanbari, Zahra, additional, Jindal, Komal, additional, Khademi, Sadaf, additional, Khare, Smith K., additional, Kurkute, Ketan Kishor, additional, Locharla, Govinda Rao, additional, Longo, Luca, additional, Marateb, Hamid Reza, additional, Moradi, Mohammad Hassan, additional, Neghabi, Mehrnoosh, additional, Nirala, Neelamshobha, additional, Nouri, Arefeh, additional, Padhy, Prabin Kumar, additional, Pal, Saurabh, additional, Pogiri, Revathi, additional, Rehman, Ateeq Ur, additional, Sadiq, Muhammad Tariq, additional, Samantray, Saunak, additional, Sengur, Abdulkadir, additional, Shah, Jainish, additional, Shah, Manan, additional, Sharan, Tripurari, additional, Sharma, Rishi Raj, additional, Sharma, Shivam, additional, Shirzadi, Mehdi, additional, Shivwanshi, Resham Raj, additional, Singh, Nameirakpam Premjit, additional, Sinha, G.R., additional, Sinha, Vikas Kumar, additional, Siuly, Siuly, additional, Taran, Sachin, additional, Upadhyay, Rahul, additional, and Yadav, Dhyan Chandra, additional
Published: 2022
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31. Radix-8 Modified Booth Fixed-Width Signed Multipliers with Error Compensation

Author: Locharla, Govinda Rao, Mahapatra, Kamala Kanta, and Ari, Samit
Published: 2021
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32. Excellent Engineering Solution in Compressor Area to Avoid Project Delay

Author: AlQaydi, Alya, additional, Awadhi, Ibrahim Al, additional, Gongade, Ashish Shivaji, additional, and Locharla, Haribabu, additional
Published: 2023
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33. Implementation of input data buffering and scheduling methodology for 8 parallel MDC FFT.

Author: Govinda Rao Locharla, K. Sudeendra Kumar, Kamala Kanta Mahapatra, and Samit Ari
Published: 2015
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34. Topology Optimization of a Steering Knuckle

Author: -, Mailapali Kumar Raja, primary, -, Jarajapu Naveen Kumar, additional, -, Boddeda Poorna Chandu, additional, -, Araku Uday Kiran, additional, -, Locharla Prem Kumar, additional, -, Bandaru Koushik, additional, and -, Kannuru Gowri Naidu, additional
Published: 2023
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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. METABOLIC SIGNATURES OF CARDIAC DYSFUNCTION ARE ASSOCIATED WITH MULTIMORBIDITY AND POST-TRANSCATHETER AORTIC VALVE IMPLANTATION MORTALITY

Author: Perry, Andrew, primary, Zhao, Shilin, additional, Murthy, Venkatesh Locharla, additional, Gupta, Deepak K., additional, Fearon, William Fuller, additional, Kim, Juyong Brian, additional, Kapadia, Samir R., additional, Kumbhani, Dharam J., additional, Gillam, Linda D., additional, Whisenant, Brian K., additional, Quader, Nishath, additional, Zajarias, Alan, additional, Mallugari, Ravinder, additional, Clark, Daniel Eugene, additional, Patel, Jay, additional, Gonzales, Holly, additional, Welt, Frederick G.P., additional, Bavry, Anthony A., additional, Coylewright, Megan, additional, Piana, Robert N., additional, Jackson, Natalie, additional, Gerszten, Robert E., additional, Lindman, Brian R., additional, Shah, Ravi, additional, and Elmariah, Sammy, additional
Published: 2023
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37. Purification-based quantum error mitigation of pair-correlated electron simulations

Author: O’Brien, TE, Anselmetti, G, Gkritsis, F, Elfving, VE, Polla, S, Huggins, WJ, Oumarou, O, Kechedzhi, K, Abanin, D, Acharya, R, Aleiner, I, Allen, R, Andersen, TI, Anderson, K, Ansmann, M, Arute, F, Arya, K, Asfaw, A, Atalaya, J, Bardin, JC, Bengtsson, A, Bortoli, G, Bourassa, A, Bovaird, J, Brill, L, Broughton, M, Buckley, B, Buell, DA, Burger, T, Burkett, B, Bushnell, N, Campero, J, Chen, Z, Chiaro, B, Chik, D, Cogan, J, Collins, R, Conner, P, Courtney, W, Crook, AL, Curtin, B, Debroy, DM, Demura, S, Drozdov, I, Dunsworth, A, Erickson, C, Faoro, L, Farhi, E, Fatemi, R, Ferreira, VS, Flores Burgos, L, Forati, E, Fowler, AG, Foxen, B, Giang, W, Gidney, C, Gilboa, D, Giustina, M, Gosula, R, Grajales Dau, A, Gross, JA, Habegger, S, Hamilton, MC, Hansen, M, Harrigan, MP, Harrington, SD, Heu, P, Hoffmann, MR, Hong, S, Huang, T, Huff, A, Ioffe, LB, Isakov, SV, Iveland, J, Jeffrey, E, Jiang, Z, Jones, C, Juhas, P, Kafri, D, Khattar, T, Khezri, M, Kieferová, M, Kim, S, Klimov, PV, Klots, AR, Korotkov, AN, Kostritsa, F, Kreikebaum, JM, Landhuis, D, Laptev, P, Lau, KM, Laws, L, Lee, J, Lee, K, Lester, BJ, Lill, AT, Liu, W, Livingston, WP, Locharla, A, Malone, FD, O’Brien, TE, Anselmetti, G, Gkritsis, F, Elfving, VE, Polla, S, Huggins, WJ, Oumarou, O, Kechedzhi, K, Abanin, D, Acharya, R, Aleiner, I, Allen, R, Andersen, TI, Anderson, K, Ansmann, M, Arute, F, Arya, K, Asfaw, A, Atalaya, J, Bardin, JC, Bengtsson, A, Bortoli, G, Bourassa, A, Bovaird, J, Brill, L, Broughton, M, Buckley, B, Buell, DA, Burger, T, Burkett, B, Bushnell, N, Campero, J, Chen, Z, Chiaro, B, Chik, D, Cogan, J, Collins, R, Conner, P, Courtney, W, Crook, AL, Curtin, B, Debroy, DM, Demura, S, Drozdov, I, Dunsworth, A, Erickson, C, Faoro, L, Farhi, E, Fatemi, R, Ferreira, VS, Flores Burgos, L, Forati, E, Fowler, AG, Foxen, B, Giang, W, Gidney, C, Gilboa, D, Giustina, M, Gosula, R, Grajales Dau, A, Gross, JA, Habegger, S, Hamilton, MC, Hansen, M, Harrigan, MP, Harrington, SD, Heu, P, Hoffmann, MR, Hong, S, Huang, T, Huff, A, Ioffe, LB, Isakov, SV, Iveland, J, Jeffrey, E, Jiang, Z, Jones, C, Juhas, P, Kafri, D, Khattar, T, Khezri, M, Kieferová, M, Kim, S, Klimov, PV, Klots, AR, Korotkov, AN, Kostritsa, F, Kreikebaum, JM, Landhuis, D, Laptev, P, Lau, KM, Laws, L, Lee, J, Lee, K, Lester, BJ, Lill, AT, Liu, W, Livingston, WP, Locharla, A, and Malone, FD
Abstract: An important measure of the development of quantum computing platforms has been the simulation of increasingly complex physical systems. Before fault-tolerant quantum computing, robust error-mitigation strategies were necessary to continue this growth. Here, we validate recently introduced error-mitigation strategies that exploit the expectation that the ideal output of a quantum algorithm would be a pure state. We consider the task of simulating electron systems in the seniority-zero subspace where all electrons are paired with their opposite spin. This affords a computational stepping stone to a fully correlated model. We compare the performance of error mitigations on the basis of doubling quantum resources in time or in space on up to 20 qubits of a superconducting qubit quantum processor. We observe a reduction of error by one to two orders of magnitude below less sophisticated techniques such as postselection. We study how the gain from error mitigation scales with the system size and observe a polynomial suppression of error with increased resources. Extrapolation of our results indicates that substantial hardware improvements will be required for classically intractable variational chemistry simulations.
Published: 2023

38. Topology Optimization of a Steering Knuckle

Author: Mailapali Kumar Raja, Jarajapu Naveen Kumar, Boddeda Poorna Chandu, Araku Uday Kiran, Locharla Prem Kumar, Bandaru Koushik, and Kannuru Gowri Naidu
Abstract: Steering knuckle is an important component from safety point of view since they are subjected to large amount of stresses. Hence to study the stress pattern in steering knuckle. ANSYS static structural workbench model is used. For analysis purpose basic model is prepared by picking data from available literature. For numerical analysis steering knuckle is prepared by using the software CATIA V5 and the stress analysis is done by FEM in ANSYS. Topology optimization have been performed for optimization of the volume and reduce the materials from the steering knuckle by using topology optimization module in ANSYS. Comparison between the results from post and pre-optimization will be done and discussed.
Published: 2023

39. Stable Quantum-Correlated Many Body States via Engineered Dissipation

Author: Mi, X., Michailidis, A. A., Shabani, S., Miao, K. C., Klimov, P. V., Lloyd, J., Rosenberg, E., Acharya, R., Aleiner, I., Andersen, T. I., Ansmann, M., Arute, F., Arya, K., Asfaw, A., Atalaya, J., Bardin, J. C., Bengtsson, A., Bortoli, G., Bourassa, A., Bovaird, J., Brill, L., Broughton, M., Buckley, B. B., Buell, D. A., Burger, T., Burkett, B., Bushnell, N., Chen, Z., Chiaro, B., Chik, D., Chou, C., Cogan, J., Collins, R., Conner, P., Courtney, W., Crook, A. L., Curtin, B., Dau, A. G., Debroy, D. M., Barba, A. Del Toro, Demura, S., Di Paolo, A., Drozdov, I. K., Dunsworth, A., Erickson, C., Faoro, L., Farhi, E., Fatemi, R., Ferreira, V. S., Forati, L. F. Burgos E., Fowler, A. G., Foxen, B., Genois, E., Giang, W., Gidney, C., Gilboa, D., Giustina, M., Gosula, R., Gross, J. A., Habegger, S., Hamilton, M. C., Hansen, M., Harrigan, M. P., Harrington, S. D., Heu, P., Hoffmann, M. R., Hong, S., Huang, T., Huff, A., Huggins, W. J., Ioffe, L. B., Isakov, S. V., Iveland, J., Jeffrey, E., Jiang, Z., Jones, C., Juhas, P., Kafri, D., Kechedzhi, K., Khattar, T., Khezri, M., Kieferova, M., Kim, S., Kitaev, A., Klots, A. R., Korotkov, A. N., Kostritsa, F., Kreikebaum, J. M., Landhuis, D., Laptev, P., Lau, K. -M., Laws, L., Lee, J., Lee, K. W., Lensky, Y. D., Lester, B. J., Lill, A. T., Liu, W., Locharla, A., Malone, F. D., Martin, O., McClean, J. R., McEwen, M., Mieszala, A., Montazeri, S., Morvan, A., Movassagh, R., Mruczkiewicz, W., Neeley, M., Neill, C., Nersisyan, A., Newman, M., Ng, J. H., Nguyen, A., Nguyen, M., Niu, M. Y., OBrien, T. E., Opremcak, A., Petukhov, A., Potter, R., Pryadko, L. P., Quintana, C., Rocque, C., Rubin, N. C., Saei, N., Sank, D., Sankaragomathi, K., Satzinger, K. J., Schurkus, H. F., Schuster, C., Shearn, M. J., Shorter, A., Shutty, N., Shvarts, V., Skruzny, J., Smith, W. C., Somma, R., Sterling, G., Strain, D., Szalay, M., Torres, A., Vidal, G., Villalonga, B., Heidweiller, C. V., White, T., Woo, B. W. K., Xing, C., Yao, Z. J., Yeh, P., Yoo, J., Young, G., Zalcman, A., Zhang, Y., Zhu, N., Zobrist, N., Neven, H., Babbush, R., Bacon, D., Boixo, S., Hilton, J., Lucero, E., Megrant, A., Kelly, J., Chen, Y., Roushan, P., Smelyanskiy, V., and Abanin, D. A.
Subjects: Quantum Physics, FOS: Physical sciences, Quantum Physics (quant-ph)
Abstract: Engineered dissipative reservoirs can steer many-body quantum systems toward correlated steady states useful for quantum simulation of high-temperature superconductivity or quantum magnetism. Using 49 superconducting qubits, we prepare low-energy states of the transverse-field Ising model via coupling to dissipative auxiliary qubits. In 1D, we observe long-range quantum correlations and a ground state fidelity that depends weakly on system sizes. In 2D, we find mutual information that extends beyond nearest neighbors. Lastly, by coupling the system to auxiliaries emulating reservoirs with different chemical potentials, we discover a new spin transport regime in the quantum Heisenberg model. Our results establish engineered dissipation as a scalable alternative to unitary evolution for preparing entangled many-body states on noisy quantum processors, and an essential tool for investigating nonequilibrium quantum phenomena.
Published: 2023

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

Author: Jesse Hoke, Matteo Ippoliti, Dmitry Abanin, Rajeev Acharya, Markus Ansmann, Frank Arute, Kunal Arya, Abraham Asfaw, Juan Atalaya, Ryan Babbush, Joseph Bardin, Andreas Bengtsson, Gina Bortoli, Alexandre Bourassa, Jenna Bovaird, Leon Brill, Michael Broughton, Bob Buckley, David Buell, Tim Burger, Brian Burkett, Nicholas Bushnell, Zijun Chen, Ben Chiaro, Desmond Chik, Charina Chou, Josh Cogan, Roberto Collins, Paul Conner, William Courtney, Alexander Crook, Ben Curtin, Alejandro Grajales Dau, Dripto Debroy, Alexander Del Toro Barba, Sean Demura, Augustin Di Paolo, Ilya Drozdov, Andrew Dunsworth, Daniel Eppens, Catherine Erickson, Lara Faoro, Edward Farhi, Reza Fatemi, Vinicius Ferreira, Leslie Flores Burgos, Ebrahim Forati, Austin Fowler, Brooks Foxen, William Giang, Craig Gidney, Dar Gilboa, Marissa Giustina, Raja Gosula, Jonathan Gross, Steve Habegger, Michael Hamilton, Monica Hansen, Matthew Harrigan, Sean Harrington, Paula Heu, Markus Hoffmann, Sabrina Hong, Trent Huang, Ashley Huff, William Huggins, Sergei Isakov, Justin Iveland, E. Jeffrey, Cody Jones, Pavol Juhas, Dvir Kafri, Kostyantyn Kechedzhi, Tanuj Khattar, Mostafa Khezri, Marika Kieferova, Seon Kim, Alexei Kitaev, Paul Klimov, Andrey Klots, Alexander Korotkov, Fedor Kostritsa, John Mark Kreikebaum, David Landhuis, Pavel Laptev, Kim-Ming Lau, Lily Laws, Joonho Lee, Kenny Lee, Yuri Lensky, Brian Lester, Alexander Lill, Wayne Liu, Aditya Locharla, Fionn Malone, Orion Martin, Jarrod McClean, Matt McEwen, Kevin Miao, Amanda Mieszala, Shirin Montazeri, Alexis Morvan, Ramis Movassagh, Wojciech Mruczkiewicz, Matthew Neeley, Charles Neill, Ani Nersisyan, Michael Newman, Jiun How Ng, Anthony Nguyen, Murray Nguyen, Murphy Niu, Thomas O'Brien, Seun Omonije, Alex Opremcak, Andre Petukhov, Rebecca Potter, Leonid Pryadko, Chris Quintana, Charles Rocque, Nicholas Rubin, Negar Saei, Daniel Sank, Kannan Sankaragomathi, Kevin Satzinger, Henry Schurkus, Christopher Schuster, Michael Shearn, Aaron Shorter, Noah Shutty, Shvarts Vladimir, Jindra Skruzny, W. Smith, Rolando Somma, George Sterling, Doug Strain, Marco Szalay, Alfredo Torres, Guifre Vidal, Benjamin Villalonga, Catherine Vollgraff Heidweiller, Theodore White, Bryan Woo, Cheng Xing, Z. Jamie Yao, Ping Yeh, Juhwan Yoo, Grayson Young, Adam Zalcman, Yaxing Zhang, Ningfeng Zhu, Nicholas Zobrist, Hartmut Neven, Dave Bacon, Sergio Boixo, Jeremy Hilton, Erik Lucero, Anthony Megrant, Julian Kelly, Yu Chen, Vadim Smelyanskiy, Xiao Mi, Vedika Khemani, and Pedram Roushan
Abstract: Measurement has a special role in quantum theory1: by collapsing the wavefunction it can enable phenomena such as teleportation2 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-time3-10 that go beyond established paradigms for characterizing phases, either in or out of equilibrium11-13. On present-day NISQ processors14, 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 mapping9,15-17 to avoid mid-circuit measurement and access different manifestations of the underlying phases—from entanglement scaling3,4 to measurement-induced teleportation18—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

41. 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

42. Review of deep learning based methods for sleep apnea detection

Author: Govinda Rao Locharla, V. K Sheela, S. Lakshmi, and Tripti Tiwari
Subjects: General Nursing, Education
Abstract: One of the most prevalent and serious causes of sleep disorders is sleep apnea syndrome. Manual identification of such disorders by investigating the EEG recordings is a time-consuming task. Hence, automatic detection of sleep apnea in EEG signals could be a preferred solution. In recent years, many deep learning algorithms are being reported for automatic sleep apnea detection. In this paper, a comprehensive review of various recently reported deep learning techniques like convolutional neural network (CNN), Bi-directional Long short-term memory (Bi-LSTM), recurrent neural network (RNN), etc., are presented and the performance of those techniques are compared.
Published: 2022

43. 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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44. Resolving catastrophic error bursts from cosmic rays in large arrays of superconducting qubits

Author: Matt McEwen, Lara Faoro, Kunal Arya, Andrew Dunsworth, Trent Huang, Seon Kim, Brian Burkett, Austin Fowler, Frank Arute, Joseph C. Bardin, Andreas Bengtsson, Alexander Bilmes, Bob B. Buckley, Nicholas Bushnell, Zijun Chen, Roberto Collins, Sean Demura, Alan R. Derk, Catherine Erickson, Marissa Giustina, Sean D. Harrington, Sabrina Hong, Evan Jeffrey, Julian Kelly, Paul V. Klimov, Fedor Kostritsa, Pavel Laptev, Aditya Locharla, Xiao Mi, Kevin C. Miao, Shirin Montazeri, Josh Mutus, Ofer Naaman, Matthew Neeley, Charles Neill, Alex Opremcak, Chris Quintana, Nicholas Redd, Pedram Roushan, Daniel Sank, Kevin J. Satzinger, Vladimir Shvarts, Theodore White, Z. Jamie Yao, Ping Yeh, Juhwan Yoo, Yu Chen, Vadim Smelyanskiy, John M. Martinis, Hartmut Neven, Anthony Megrant, Lev Ioffe, Rami Barends, Laboratoire de Physique Théorique et Hautes Energies (LPTHE), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), HEP, INSPIRE, and Faoro, Lara
Subjects: Quantum Physics, [SPI] Engineering Sciences [physics], [PHYS.PHYS.PHYS-GEN-PH] Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], FOS: Physical sciences, General Physics and Astronomy, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], [SPI]Engineering Sciences [physics], 0103 physical sciences, Quantum Physics (quant-ph), 010306 general physics, 0210 nano-technology
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

45. 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

46. Formation of robust bound states of interacting microwave photons

Author: A. Morvan, T. I. Andersen, X. Mi, C. Neill, A. Petukhov, K. Kechedzhi, D. A. Abanin, A. Michailidis, R. Acharya, F. Arute, K. Arya, A. Asfaw, J. Atalaya, J. C. Bardin, J. Basso, A. Bengtsson, G. Bortoli, A. Bourassa, J. Bovaird, L. Brill, M. Broughton, B. B. Buckley, D. A. Buell, T. Burger, B. Burkett, N. Bushnell, Z. Chen, B. Chiaro, R. Collins, P. Conner, W. Courtney, A. L. Crook, B. Curtin, D. M. Debroy, A. Del Toro Barba, S. Demura, A. Dunsworth, D. Eppens, C. Erickson, L. Faoro, E. Farhi, R. Fatemi, L. Flores Burgos, E. Forati, A. G. Fowler, B. Foxen, W. Giang, C. Gidney, D. Gilboa, M. Giustina, A. Grajales Dau, J. A. Gross, S. Habegger, M. C. Hamilton, M. P. Harrigan, S. D. Harrington, M. Hoffmann, S. Hong, T. Huang, A. Huff, W. J. Huggins, S. V. Isakov, J. Iveland, E. Jeffrey, Z. Jiang, C. Jones, P. Juhas, D. Kafri, T. Khattar, M. Khezri, M. Kieferová, S. Kim, A. Y. Kitaev, P. V. Klimov, A. R. Klots, A. N. Korotkov, F. Kostritsa, J. M. Kreikebaum, D. Landhuis, P. Laptev, K.-M. Lau, L. Laws, J. Lee, K. W. Lee, B. J. Lester, A. T. Lill, W. Liu, A. Locharla, F. Malone, O. Martin, J. R. McClean, M. McEwen, B. Meurer Costa, K. C. Miao, M. Mohseni, S. Montazeri, E. Mount, W. Mruczkiewicz, O. Naaman, M. Neeley, A. Nersisyan, M. Newman, A. Nguyen, M. Nguyen, M. Y. Niu, T. E. O’Brien, R. Olenewa, A. Opremcak, R. Potter, C. Quintana, N. C. Rubin, N. Saei, D. Sank, K. Sankaragomathi, K. J. Satzinger, H. F. Schurkus, C. Schuster, M. J. Shearn, A. Shorter, V. Shvarts, J. Skruzny, W. C. Smith, D. Strain, G. Sterling, Y. Su, M. Szalay, A. Torres, G. Vidal, B. Villalonga, C. Vollgraff-Heidweiller, T. White, C. Xing, Z. Yao, P. Yeh, J. Yoo, A. Zalcman, Y. Zhang, N. Zhu, H. Neven, D. Bacon, J. Hilton, E. Lucero, R. Babbush, S. Boixo, A. Megrant, J. Kelly, Y. Chen, V. Smelyanskiy, I. Aleiner, L. B. Ioffe, and P. Roushan
Subjects: Photons, Quantum Physics, Multidisciplinary, Condensed Matter - Mesoscale and Nanoscale Physics, General Science & Technology, Reproduction, FOS: Physical sciences, Electrons, Condensed Matter - Other Condensed Matter, Fees and Charges, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Microwaves, Quantum Physics (quant-ph), Other Condensed Matter (cond-mat.other)
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., 7 pages + 15 pages supplements
Published: 2022

47. Time-crystalline eigenstate order on a quantum processor

Author: Julian Kelly, Alexander Bilmes, Vedika Khemani, Seon Kim, Alexei Kitaev, Murphy Yuezhen Niu, J. Hilton, Orion Martin, Craig Gidney, Bob B. Buckley, Thomas E. O'Brien, Jarrod R. McClean, Alexander N. Korotkov, Pavel Laptev, Tanuj Khattar, Sabrina Hong, Daniel Eppens, Alan Ho, Aditya Locharla, Ofer Naaman, Ping Yeh, Juan Atalaya, Sean D. Harrington, Frank Arute, Roberto Collins, Joao Marcos Vensi Basso, Doug Strain, Matthew P. Harrigan, Zhang Jiang, Joonho Lee, Ami Greene, Alan R. Derk, Roderich Moessner, Bálint Pató, William J. Huggins, Trevor McCourt, Ashley Huff, Joseph C. Bardin, Andre Petukhov, Fedor Kostritsa, Michael Newman, Cody Jones, Sean Demura, Shivaji Lal Sondhi, B. Burkett, Sergio Boixo, Jonathan H. Gross, David A. Buell, Kevin J. Satzinger, Michael Broughton, Daniel Sank, Masoud Mohseni, Lev Ioffe, Yuan Su, Shirin Montazeri, Xiao Mi, Eric Ostby, Marissa Giustina, David Landhuis, Z. Jamie Yao, Kenny Lee, Kunal Arya, Pedram Roushan, Hartmut Neven, Sergei V. Isakov, Andrew Dunsworth, Zijun Chen, Matteo Ippoliti, Matthew Neeley, Nicholas C. Rubin, Austin G. Fowler, Anthony Megrant, Marco Szalay, Trent Huang, Evan Jeffrey, Leon Brill, Justin Iveland, Paul V. Klimov, Matthew D. Trevithick, William Courtney, Nicholas Bushnell, Theodore White, Alexandre Bourassa, E. Lucero, Edward Farhi, Vladimir Shvarts, Dripto M. Debroy, Benjamin Villalonga, Wojciech Mruczkiewicz, Chris Quintana, Juhwan Yoo, Benjamin Chiaro, Dvir Kafri, Brooks Foxen, Vadim Smelyanskiy, Ryan Babbush, Kostyantyn Kechedzhi, Charles Neill, Yu Chen, Andreas Bengtsson, Matt McEwen, A. Opremcak, Kevin C. Miao, Adam Zalcman, and Catherine Erickson
Subjects: Thermal equilibrium, Physics, Phase transition, Multidisciplinary, Quantum decoherence, Quantum information, Quantum simulator, Article, Phase Transition, Cold Temperature, Phase transitions and critical phenomena, Qubit, Thermodynamics, Statistical physics, Quantum simulation, Quantum, Quantum computer
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., A study establishes a scalable approach to engineer and characterize a many-body-localized discrete time crystal phase on a superconducting quantum processor.
Published: 2021

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

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

49. Noise-resilient edge modes on a chain of superconducting qubits

Author: Mi, X., primary, Sonner, M., additional, Niu, M. Y., additional, Lee, K. W., additional, Foxen, B., additional, Acharya, R., additional, Aleiner, I., additional, Andersen, T. I., additional, Arute, F., additional, Arya, K., additional, Asfaw, A., additional, Atalaya, J., additional, Bardin, J. C., additional, Basso, J., additional, Bengtsson, A., additional, Bortoli, G., additional, Bourassa, A., additional, Brill, L., additional, Broughton, M., additional, Buckley, B. B., additional, Buell, D. A., additional, Burkett, B., additional, Bushnell, N., additional, Chen, Z., additional, Chiaro, B., additional, Collins, R., additional, Conner, P., additional, Courtney, W., additional, Crook, A. L., additional, Debroy, D. M., additional, Demura, S., additional, Dunsworth, A., additional, Eppens, D., additional, Erickson, C., additional, Faoro, L., additional, Farhi, E., additional, Fatemi, R., additional, Flores, L., additional, Forati, E., additional, Fowler, A. G., additional, Giang, W., additional, Gidney, C., additional, Gilboa, D., additional, Giustina, M., additional, Dau, A. G., additional, Gross, J. A., additional, Habegger, S., additional, Harrigan, M. P., additional, Hoffmann, M., additional, Hong, S., additional, Huang, T., additional, Huff, A., additional, Huggins, W. J., additional, Ioffe, L. B., additional, Isakov, S. V., additional, Iveland, J., additional, Jeffrey, E., additional, Jiang, Z., additional, Jones, C., additional, Kafri, D., additional, Kechedzhi, K., additional, Khattar, T., additional, Kim, S., additional, Kitaev, A. Y., additional, Klimov, P. V., additional, Klots, A. R., additional, Korotkov, A. N., additional, Kostritsa, F., additional, Kreikebaum, J. M., additional, Landhuis, D., additional, Laptev, P., additional, Lau, K.-M., additional, Lee, J., additional, Laws, L., additional, Liu, W., additional, Locharla, A., additional, Martin, O., additional, McClean, J. R., additional, McEwen, M., additional, Meurer Costa, B., additional, Miao, K. C., additional, Mohseni, M., additional, Montazeri, S., additional, Morvan, A., additional, Mount, E., additional, Mruczkiewicz, W., additional, Naaman, O., additional, Neeley, M., additional, Neill, C., additional, Newman, M., additional, O’Brien, T. E., additional, Opremcak, A., additional, Petukhov, A., additional, Potter, R., additional, Quintana, C., additional, Rubin, N. C., additional, Saei, N., additional, Sank, D., additional, Sankaragomathi, K., additional, Satzinger, K. J., additional, Schuster, C., additional, Shearn, M. J., additional, Shvarts, V., additional, Strain, D., additional, Su, Y., additional, Szalay, M., additional, Vidal, G., additional, Villalonga, B., additional, Vollgraff-Heidweiller, C., additional, White, T., additional, Yao, Z., additional, Yeh, P., additional, Yoo, J., additional, Zalcman, A., additional, Zhang, Y., additional, Zhu, N., additional, Neven, H., additional, Bacon, D., additional, Hilton, J., additional, Lucero, E., additional, Babbush, R., additional, Boixo, S., additional, Megrant, A., additional, Chen, Y., additional, Kelly, J., additional, Smelyanskiy, V., additional, Abanin, D. A., additional, and Roushan, P., additional
Published: 2022
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50. 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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