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598 results on '"Pucher, P."'

1. Optical Nuclear Electric Resonance as Single Qubit Gate for Trapped Neutral Atoms

Author

Krondorfer, Johannes K., Pucher, Sebastian, Diez, Matthias, Blatt, Sebastian, and Hauser, Andreas W.

Subjects
Quantum Physics, Physics - Atomic Physics
Abstract

The precise control of nuclear spin states is crucial for a wide range of quantum technology applications. Here, we propose a fast and robust single qubit gate in $^{87}$Sr, utilizing the concept of optical nuclear electric resonance (ONER). ONER exploits the interaction between the quadrupole moment of a nucleus and the electric field gradient generated by its electronic environment, enabling spin level transitions via amplitude-modulated laser light. We investigate the hyperfine structure of the 5s$^2$ $^1S_{0}\rightarrow{}$ 5s5p $^3P_1$ optical transition in neutral $^{87}$Sr, and identify the magnetic field strengths and laser parameters necessary to drive spin transitions between the $m_I$ = -9/2 and $m_I$ = -5/2 hyperfine levels in the ground state. Our simulations show that ONER could enable faster spin operations compared to the state-of-the-art oscillations in this 'atomic qubit'. Moreover, we show that the threshold for fault-tolerant quantum computing can be surpassed even in the presence of typical noise sources. These results pave the way for significant advances in nuclear spin control, opening new possibilities for quantum memories and other quantum technologies.

Published
2025

2. The exact subgraph hierarchy and its local variant for the stable set problem for Paley graphs

Author

Gaar, Elisabeth and Pucher, Dunja

Subjects
Mathematics - Optimization and Control, Computer Science - Discrete Mathematics, 90C27, 90C22
Abstract

The stability number of a graph, defined as the cardinality of the largest set of pairwise non-adjacent vertices, is NP-hard to compute. The exact subgraph hierarchy (ESH) provides a sequence of increasingly tighter upper bounds on the stability number, starting with the Lov\'asz theta function at the first level and including all exact subgraph constraints of subgraphs of order $k$ into the semidefinite program to compute the Lov\'asz theta function at level $k$. In this paper, we investigate the ESH for Paley graphs, a class of strongly regular, vertex-transitive graphs. We show that for Paley graphs, the bounds obtained from the ESH remain the Lov\'asz theta function up to a certain threshold level, i.e., the bounds of the ESH do not improve up to a certain level. To overcome this limitation, we introduce the local ESH for the stable set problem for vertex-transitive graphs such as Paley graphs. We prove that this new hierarchy provides upper bounds on the stability number of vertex-transitive graphs that are at least as tight as those obtained from the ESH. Additionally, our computational experiments reveal that the local ESH produces superior bounds compared to the ESH for Paley graphs., Comment: 25 pages, 3 figures, 2 tables

Published
2024

3. Quantum computing and the stable set problem

Author

Krpan, Aljaž, Povh, Janez, and Pucher, Dunja

Subjects
Mathematics - Optimization and Control, Primary 90C27, Secondary 81P68
Abstract

Given an undirected graph, the stable set problem asks to determine the cardinality of the largest subset of pairwise non-adjacent vertices. This value is called the stability number of the graph, and its computation is an NP-hard problem. In this paper, we solve the stable set problem using the D-wave quantum annealer. By formulating the problem as a quadratic unconstrained binary optimization problem with the penalty method, we show its optimal value equals the graph's stability number for specific penalty values. However, D-Wave's quantum annealer is a heuristic, so the solutions may be far from the optimum and may not represent stable sets. To address these, we introduce a post-processing procedure that identifies samples that could lead to improved solutions. Additionally, we propose a partitioning method to handle larger instances that cannot be embedded on D-Wave's quantum processing unit. Finally, we investigate how different penalty parameter values affect the solutions' quality. Extensive computational results show that the post-processing procedure significantly improves the solution quality, while the partitioning method successfully extends our approach to medium-size instances.

Published
2024

4. Strong electrostatic control of excitonic features in MoS$_2$ by a free-standing ultrahigh-$\kappa$ ferroelectric perovskite

Author

Pucher, Thomas, Puebla, Sergio, Zamora, Victor, Viso, Estrella Sánchez, Rouco, Victor, Leon, Carlos, Garcia-Hernandez, Mar, Santamaria, Jacobo, Munuera, Carmen, and Castellanos-Gomez, Andres

Subjects
Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

We present the electrostatic control of photoluminescence of monolayer MoS$_2$ at room temperature via integration of free-standing BaTiO$_3$ (BTO), a ferroelectric perovskite oxide, layers. We show that the use of BTO leads to highly tunable exciton emission of MoS$_2$ in a minimal range of gate voltages, effectively controlling the neutral excitons to charged excitons (trions) conversion. Due to BTO's ferroelectric polarization-induced doping we observe large peak emission shifts as well as a large and tunable A trion binding energy in the range of 40-100 meV. To further investigate the efficacy of electrostatic control, we compared our measurements with those carried out when the BTO is replaced by a hexagonal boron nitride (hBN) dielectric layer of comparable thickness, confirming BTO's superior gating properties and thus lower power consumption. Additionally, we take advantage of the ferroelectric switching of BTO by fabricating devices where the BTO layer is decoupled from the gate electrode with a SiO$_2$ layer. Choosing to isolate the BTO allows us to induce large remanent behavior of MoS$_2$'s excitonic features, observing hysteretic behavior in the peak energy ratio between A exciton and its trion, as well as hysteretic behavior in the doping-related trion energy shift. This study illustrates the rich physics involved in combining free-standing complex oxide layers with two-dimensional materials.

Published
2024

5. Widespread horse-based mobility arose around 2200 BCE in Eurasia.

Author

Librado, Pablo, Tressières, Gaetan, Chauvey, Lorelei, Fages, Antoine, Khan, Naveed, Schiavinato, Stéphanie, Calvière-Tonasso, Laure, Kusliy, Mariya, Gaunitz, Charleen, Liu, Xuexue, Wagner, Stefanie, Der Sarkissian, Clio, Seguin-Orlando, Andaine, Perdereau, Aude, Aury, Jean-Marc, Southon, John, Shapiro, Beth, Bouchez, Olivier, Donnadieu, Cécile, Collin, Yvette, Gregersen, Kristian, Jessen, Mads, Christensen, Kirsten, Claudi-Hansen, Lone, Pruvost, Mélanie, Pucher, Erich, Vulic, Hrvoje, Novak, Mario, Rimpf, Andrea, Turk, Peter, Reiter, Simone, Brem, Gottfried, Schwall, Christoph, Barrey, Éric, Robert, Céline, Degueurce, Christophe, Horwitz, Liora, Klassen, Lutz, Rasmussen, Uffe, Kveiborg, Jacob, Johannsen, Niels, Makowiecki, Daniel, Makarowicz, Przemysław, Szeliga, Marcin, Ilchyshyn, Vasyl, Rud, Vitalii, Romaniszyn, Jan, Mullin, Victoria, Verdugo, Marta, Bradley, Daniel, Cardoso, João, Valente, Maria, Telles Antunes, Miguel, Ameen, Carly, Thomas, Richard, Ludwig, Arne, Marzullo, Matilde, Prato, Ornella, Bagnasco Gianni, Giovanna, Tecchiati, Umberto, Granado, José, Schlumbaum, Angela, Deschler-Erb, Sabine, Mráz, Monika, Boulbes, Nicolas, Gardeisen, Armelle, Mayer, Christian, Döhle, Hans-Jürgen, Vicze, Magdolna, Kosintsev, Pavel, Kyselý, René, Peške, Lubomír, OConnor, Terry, Ananyevskaya, Elina, Shevnina, Irina, Logvin, Andrey, Kovalev, Alexey, Iderkhangai, Tumur-Ochir, Sablin, Mikhail, Dashkovskiy, Petr, Graphodatsky, Alexander, Merts, Ilia, Merts, Viktor, Kasparov, Aleksei, Pitulko, Vladimir, Onar, Vedat, Öztan, Aliye, Arbuckle, Benjamin, McColl, Hugh, Renaud, Gabriel, Khaskhanov, Ruslan, Demidenko, Sergey, Kadieva, Anna, Atabiev, Biyaslan, Sundqvist, Marie, Lindgren, Gabriella, López-Cachero, F, Albizuri, Silvia, Trbojević Vukičević, Tajana, and Rapan Papeša, Anita

Abstract

Horses revolutionized human history with fast mobility1. However, the timeline between their domestication and their widespread integration as a means of transport remains contentious2-4. Here we assemble a collection of 475 ancient horse genomes to assess the period when these animals were first reshaped by human agency in Eurasia. We find that reproductive control of the modern domestic lineage emerged around 2200 BCE, through close-kin mating and shortened generation times. Reproductive control emerged following a severe domestication bottleneck starting no earlier than approximately 2700 BCE, and coincided with a sudden expansion across Eurasia that ultimately resulted in the replacement of nearly every local horse lineage. This expansion marked the rise of widespread horse-based mobility in human history, which refutes the commonly held narrative of large horse herds accompanying the massive migration of steppe peoples across Europe around 3000 BCE and earlier3,5. Finally, we detect significantly shortened generation times at Botai around 3500 BCE, a settlement from central Asia associated with corrals and a subsistence economy centred on horses6,7. This supports local horse husbandry before the rise of modern domestic bloodlines.

Published
2024

6. Practical Experience with Stable Set and Coloring Relaxations

Author

Pucher, Dunja and Rendl, Franz

Subjects
Mathematics - Optimization and Control, 90C27, 90C22
Abstract

Stable Set and Graph Coloring belong to the class of NP-hard optimization problems on graphs. It is well known that even near-optimal solutions for these problems are difficult to find in polynomial time. The Lov\'asz theta function, introduced by Lov\'asz in the late 1970s, provides a powerful tool in the study of these problems. It can be expressed as the optimal value of a semidefinite program and serves as a relaxation for both problems. Considerable effort has been devoted to investigating additional cutting planes to strengthen these relaxations. In our work, we use these models and consider new classes of cutting planes based on small cliques and cycles contained in the underlying graph. We demonstrate that identifying such violated constraints can be done efficiently and that they often lead to significant improvements over previous bounds. However, our computational experiments also show that the quality of these improvements may decrease with problem size, and in some instances, no improvement is observed.

Published
2024

7. Fine-Structure Qubit Encoded in Metastable Strontium Trapped in an Optical Lattice

Author

Pucher, S., Klüsener, V., Spriestersbach, F., Geiger, J., Schindewolf, A., Bloch, I., and Blatt, S.

Subjects
Quantum Physics, Condensed Matter - Quantum Gases, Physics - Atomic Physics
Abstract

We demonstrate coherent control of the fine-structure qubit in neutral strontium atoms. This qubit is encoded in the metastable $^3\mathrm{P}_2$ and $^3\mathrm{P}_0$ states, coupled by a Raman transition. Using a magnetic quadrupole transition, we demonstrate coherent state-initialization of this THz qubit. We show Rabi oscillations with more than 60 coherent cycles and single-qubit rotations on the $\mu$s scale. With spin-echo, we demonstrate coherence times of tens of ms. Our results pave the way for fast quantum information processors and highly tunable quantum simulators with two-electron atoms., Comment: 5 pages, 4 figures, 4 pages supplemental material

Published
2024
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8. Coherent excitation of a $\mu$Hz scale optical magnetic quadrupole transition

Author

Klüsener, V., Pucher, S., Yankelev, D., Trautmann, J., Spriestersbach, F., Filin, D., Porsev, S. G., Safronova, M. S., Bloch, I., and Blatt, S.

Subjects
Physics - Atomic Physics, Condensed Matter - Quantum Gases, Quantum Physics
Abstract

We report on the coherent excitation of the ultranarrow $^{1}\mathrm{S}_0$-$^{3}\mathrm{P}_2$ magnetic quadrupole transition in $^{88}\mathrm{Sr}$. By confining atoms in a state insensitive optical lattice, we achieve excitation fractions of 97(1)% and observe linewidths as narrow as 58(1) Hz. With Ramsey spectroscopy, we find coherence times of 14(1) ms, which can be extended to 266(36) ms using a spin-echo sequence. We determine the linewidth of the M2 transition to 24(7) $\mu$Hz, confirming longstanding theoretical predictions. These results establish an additional clock transition in strontium and pave the way for applications of the metastable $^{3}\mathrm{P}_2$ state in quantum computing and quantum simulations., Comment: 6 pages, 4 figures, 5 pages supplemental material

Published
2024
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12. Advancing stable set problem solutions through quantum annealers

Author

Povh, Janez and Pucher, Dunja

Subjects
Mathematics - Optimization and Control, Quantum Physics, 90C27, 81P68
Abstract

We assess the performance of D-wave quantum solvers for solving the stable set problem in a graph, one of the most studied NP-hard problems. We perform computations on some instances from the literature with up to 125 vertices and compare the quality of the obtained solutions with known optimum solutions. It turns out that the hybrid solver gives very good results, while the Quantum Processing Unit solver shows rather modest performance overall.

Published
2023

14. Feedback-cooling the fundamental torsional mechanical mode of a tapered optical fiber to 30 mK

Author

Tebbenjohanns, Felix, Jia, Jihao, Antesberger, Michael, Prasad, Adarsh Shankar, Pucher, Sebastian, Rauschenbeutel, Arno, Volz, Jürgen, and Schneeweiss, Philipp

Subjects
Physics - Optics, Physics - Instrumentation and Detectors
Abstract

Tapered optical fibers (TOFs) are used in many areas of physics and optical technologies ranging from coupling light into nanophotonic components to optical sensing and amplification to interfacing quantum emitters. Here, we study the fundamental torsional mechanical mode of the nanofiber-waist of a TOF using laser light. We find that this oscillator features a quality factor of up to $10^7$ and a $Qf$ product of 1 THz. We damp the thermal motion from room temperature to 28(7) mK by means of active feedback. Our results might enable new types of fiber-based sensors and lay the foundation for a novel hybrid quantum optomechanical platform.

Published
2023
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17. Stable-Set and Coloring bounds based on 0-1 quadratic optimization

Author

Pucher, Dunja and Rendl, Franz

Subjects
Mathematics - Optimization and Control, 90C22
Abstract

We consider semidefinite relaxations of Stable-Set and Coloring, which are based on quadratic 0-1 optimization. Information about the stability number and the chromatic number is hidden in the objective function. This leads to simplified relaxations which depend mostly on the number of vertices of the graph. We also propose tightenings of the relaxations which are based on the maximal cliques of the underlying graph. Computational results on graphs from the literature show the strong potential of this new approach.

Published
2022
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18. Observation of superradiant bursts in a cascaded quantum system

Author

Liedl, Christian, Tebbenjohanns, Felix, Bach, Constanze, Pucher, Sebastian, Rauschenbeutel, Arno, and Schneeweiss, Philipp

Subjects
Quantum Physics, Physics - Atomic Physics
Abstract

Dicke superradiance describes the collective radiative decay of a fully inverted ensemble of two-level atoms. We experimentally investigate this effect for a chiral, i.e.,~direction-dependent light--matter coupling. Despite a fundamentally different interaction Hamiltonian which has a reduced symmetry compared to the standard Dicke case, we do observe a superradiant burst emission. The burst occurs above a threshold number of atoms, and its peak power scales faster with the number of atoms than in the case of free-space Dicke superradiance. We measure the first-order coherence of the burst emission and experimentally distinguish two regimes, one dominated by the coherence induced during the excitation process and the other governed by vacuum fluctuations. Our results shed light on the collective radiative dynamics of cascaded quantum many-body systems, i.e., a system in which each quantum emitter is only driven by light radiated by emitters that are further upstream in the cascade. Our findings may turn out useful for generating multi-photon Fock states as a resource for quantum technologies.

Published
2022
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19. Advances in Catchment Science, Hydrochemistry, and Aquatic Ecology Enabled by High-Frequency Water Quality Measurements

Author

Bieroza, Magdalena, Acharya, Suman, Benisch, Jakob, Borg, Rebecca N ter, Hallberg, Lukas, Negri, Camilla, Pruitt, Abagael, Pucher, Matthias, Saavedra, Felipe, Staniszewska, Kasia, Veen, Sofie GM van’t, Vincent, Anna, Winter, Carolin, Basu, Nandita B, Jarvie, Helen P, and Kirchner, James W

Subjects
Water Quality, Hydrobiology, Rivers, Forecasting, Environmental Monitoring, Catchment science, stream hydrochemistry, aquatic ecology, high-frequency, water quality monitoring, optical sensors, Environmental Sciences
Abstract

High-frequency water quality measurements in streams and rivers have expanded in scope and sophistication during the last two decades. Existing technology allows in situ automated measurements of water quality constituents, including both solutes and particulates, at unprecedented frequencies from seconds to subdaily sampling intervals. This detailed chemical information can be combined with measurements of hydrological and biogeochemical processes, bringing new insights into the sources, transport pathways, and transformation processes of solutes and particulates in complex catchments and along the aquatic continuum. Here, we summarize established and emerging high-frequency water quality technologies, outline key high-frequency hydrochemical data sets, and review scientific advances in key focus areas enabled by the rapid development of high-frequency water quality measurements in streams and rivers. Finally, we discuss future directions and challenges for using high-frequency water quality measurements to bridge scientific and management gaps by promoting a holistic understanding of freshwater systems and catchment status, health, and function.

Published
2023

20. Observation of oscillatory Raman gain associated with two-photon Rabi oscillations of nanofiber-coupled atoms

Author

Liedl, Christian, Pucher, Sebastian, Schneeweiss, Philipp, Yatsenko, Leonid P., and Rauschenbeutel, Arno

Subjects
Physics - Atomic Physics, Quantum Physics
Abstract

Quantum emitters with a $\Lambda$-type level structure enable numerous protocols and applications in quantum science and technology. Understanding and controlling their dynamics is, therefore, one of the central research topics in quantum optics. Here, we drive two-photon Rabi oscillations between the two ground states of cesium atoms and observe the associated oscillatory Raman gain and absorption that stems from the atom-mediated coherent photon exchange between the two drive fields. The atoms are efficiently and homogeneously coupled with the probe field by means of a nanofiber-based optical interface. We study the dependence of the two-photon Rabi frequency on the system parameters and observe Autler-Townes splitting in the probe transmission spectrum. Beyond shedding light on the fundamental processes underlying two-photon Rabi oscillations, our method could also be used to investigate (quantum) correlations between the two drive fields as well as the dynamical establishment of electromagnetically induced transparency.

Published
2022
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22. Collective excitation and decay of waveguide-coupled atoms: from timed Dicke states to inverted ensembles

Author

Liedl, Christian, Pucher, Sebastian, Tebbenjohanns, Felix, Schneeweiss, Philipp, and Rauschenbeutel, Arno

Subjects
Quantum Physics, Physics - Atomic Physics
Abstract

The collective absorption and emission of light by an ensemble of atoms is at the heart of many fundamental quantum optical effects and the basis for numerous applications. However, beyond weak excitation, both experiment and theory become increasingly challenging. Here, we explore the regimes from weak excitation to inversion with ensembles of up to one thousand atoms that are trapped and optically interfaced using the evanescent field surrounding an optical nanofiber. We realize strong inversion, with about 80% of the atoms being excited, and study their subsequent radiative decay into the guided modes. The data is very well described by a simple model that assumes a cascaded interaction of the guided light with the atoms. Our results contribute to the fundamental understanding of the collective interaction of light and matter and are relevant for applications ranging from quantum memories to sources of nonclassical light to optical frequency standards.

Published
2022
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28. Predictors of anastomotic leak and conduit necrosis after oesophagectomy: Results from the oesophago-gastric anastomosis audit (OGAA)

Author

Halle-Smith, J.M., Kamarajah, S.K., Evans, R.P.T., Nepogodiev, D., Hodson, J., Bundred, J.R., Gockel, I., Gossage, J.A., Isik, A., Kauppila, J.H., Kidane, B., Mahendran, H.A., Negoi, I., Okonta, K.E., Sayyed, R., van Hillegersberg, R., Vohra, R.S., Wijnhoven, B.P.L., Singh, P., Griffiths, E.A., Alderson, D., Bundred, J., Gossage, J., Jefferies, B., McKay, S., Mohamed, I., Siaw- Acheampong, K., Vohra, R., Wanigasooriya, K., Whitehouse, T., Gjata, A., Moreno, J.I., Takeda, F.R., Guevara Castro, R., Bekele, A., Harustiak, T., Kechagias, A., Bagajevas, A., Kennedy, A., Da Roit, A., Azagra, J.S., Mejía-Fernández, L., El Kafsi, J., Sayyed, R.H., Sousa, M., Sampaio, A.S., Blanco, R., Wallner, B., Schneider, P.M., Hsu, P.K., Gananadha, S., Wills, V., Devadas, M., Duong, C., Talbot, M., Hii, M.W., Jacobs, R., Andreollo, N.A., Johnston, B., Darling, G., Isaza-Restrepo, A., Rosero, G., Arias- Amézquita, F., Raptis, D., Gaedcke, J., Reim, D., Izbicki, J., Egberts, J.H., Dikinis, S., Kjaer, D.W., Larsen, M.H., Achiam, M.P., Saarnio, J., Theodorou, D., Liakakos, T., Korkolis, D.P., Robb, W.B., Collins, C., Murphy, T., Reynolds, J., Tonini, V., Migliore, M., Bonavina, L., Valmasoni, M., Bardini, R., Weindelmayer, J., Terashima, M., White, R.E., Alghunaim, E., Elhadi, M., Leon-Takahashi, A.M., Medina-Franco, H., Lau, P.C., Heisterkamp, J., Rosman, C., Beban, G., Babor, R., Gordon, A., Rossaak, J.I., Pal, K.M.I., Qureshi, A.U., Naqi, S.A., Syed, A.A., Barbosa, J., Vicente, C.S., Leite, J., Freire, J., Casaca, R., Costa, R.C.T., Scurtu, R.R., Mogoanta, S.S., Bolca, C., Constantinoiu, S., Sekhniaidze, D., Bjelović, M., So, J.B.Y., Gačevski, G., Loureiro, C., Pera, M., Bianchi, A., Moreno Gijón, M., Martín Fernández, J., Trugeda Carrera, M.S., Vallve-Bernal, M., Cítores Pascual, M.A., Elmahi, S., Halldestam, I., Hedberg, J., Mönig, S., Gutknecht, S., Tez, M., Guner, A., Tirnaksiz, M.B., Colak, E., Sevinç, B., Hindmarsh, A., Khan, I., Khoo, D., Byrom, R., Gokhale, J., Wilkerson, P., Jain, P., Chan, D., Robertson, K., Iftikhar, S., Skipworth, R., Forshaw, M., Higgs, S., Nijjar, R., Viswanath, Y.K.S., Turner, P., Dexter, S., Boddy, A., Allum, W.H., Oglesby, S., Cheong, E., Beardsmore, D., Maynard, N., Berrisford, R., Mercer, S., Puig, S., Melhado, R., Kelty, C., Underwood, T., Dawas, K., Lewis, W., Al-Bahrani, A., Bryce, G., Thomas, M., Arndt, A.T., Palazzo, F., Meguid, R.A., Fergusson, J., Beenen, E., Mosse, C., Salim, J., Cheah, S., Wright, T., Cerdeira, M.P., McQuillan, P., Richardson, M., Liem, H., Spillane, J., Yacob, M., Albadawi, F., Thorpe, T., Dingle, A., Cabalag, C., Loi, K., Fisher, O.M., Ward, S., Read, M., Johnson, M., Bassari, R., Bui, H., Cecconello, I., Sallum, R.A.A., da Rocha, J.R.M., Lopes, L.R., Tercioti, V., Coelho, J.D.S., Ferrer, J.A.P., Buduhan, G., Tan, L., Srinathan, S., Shea, P., Yeung, J., Allison, F., Carroll, P., Vargas-Barato, F., Gonzalez, F., Ortega, J., Nino-Torres, L., Beltrán-García, T.C., Castilla, L., Pineda, M., Bastidas, A., Gómez-Mayorga, J., Cortés, N., Cetares, C., Caceres, S., Duarte, S., Pazdro, A., Snajdauf, M., Faltova, H., Sevcikova, M., Mortensen, P.B., Katballe, N., Ingemann, T., Morten, B., Kruhlikava, I., Ainswort, A.P., Stilling, N.M., Eckardt, J., Holm, J., Thorsteinsson, M., Siemsen, M., Brandt, B., Nega, B., Teferra, E., Tizazu, A., Koivukangas, V., Meriläinen, S., Gruetzmann, R., Krautz, C., Weber, G., Golcher, H., Emons, G., Azizian, A., Ebeling, M., Niebisch, S., Kreuser, N., Albanese, G., Hesse, J., Volovnik, L., Boecher, U., Reeh, M., Triantafyllou, S., Schizas, D., Michalinos, A., Balli, E., Mpoura, M., Charalabopoulos, A., Manatakis, D.K., Balalis, D., Bolger, J., Baban, C., Mastrosimone, A., McAnena, O., Quinn, A., Ó Súilleabháin, C.B., Hennessy, M.M., Ivanovski, I., Khizer, H., Ravi, N., Donlon, N., Cervellera, M., Vaccari, S., Bianchini, S., Sartarelli, l, Asti, E., Bernardi, D., Merigliano, S., Provenzano, L., Scarpa, M., Saadeh, L., Salmaso, B., De Manzoni, G., Giacopuzzi, S., La Mendola, R., De Pasqual, C.A., Tsubosa, Y., Niihara, M., Irino, T., Makuuchi, R., Ishii, K., Mwachiro, M., Fekadu, A., Odera, A., Mwachiro, E., AlShehab, D., Ahmed, H.A., Shebani, A.O., Elhadi, A., Elnagar, F.A., Elnagar, H.F., Makkai-Popa, S.T., Wong, L.F., Yr, Tan, S, Thannimalai, Ca, Ho, Ws, Pang, Jh, Tan, Hnl, Basave, Cortés-González, R., Lagarde, S.M., van Lanschot, J.J.B., Cords, C., Jansen, W.A., Martijnse, I., Matthijsen, R., Bouwense, S., Klarenbeek, B., Verstegen, M., van Workum, F., Ruurda, J.P., van der Sluis, P.C., de Maat, M., Evenett, N., Johnston, P., Patel, R., MacCormick, A., Young, M., Smith, B., Ekwunife, C., Memon, A.H., Shaikh, K., Wajid, A., Khalil, N., Haris, M., Mirza, Z.U., Qudus, S.B.A., Sarwar, M.Z., Shehzadi, A., Raza, A., Jhanzaib, M.H., Farmanali, J., Zakir, Z., Shakeel, O., Nasir, I., Khattak, S., Baig, M., Noor, M.A., Ahmed, H.H., Naeem, A., Pinho, A.C., da Silva, R., Bernardes, A., Campos, J.C., Matos, H., Braga, T., Monteiro, C., Ramos, P., Cabral, F., Gomes, M.P., Martins, P.C., Correia, A.M., Videira, J.F., Ciuce, C., Drasovean, R., Apostu, R., Paitici, S., Racu, A.E., Obleaga, C.V., Beuran, M., Stoica, B., Ciubotaru, C., Negoita, V., Cordos, I., Birla, R.D., Predescu, D., Hoara, P.A., Tomsa, R., Shneider, V., Agasiev, M., Ganjara, I., Gunjić, D., Veselinović, M., Babič, T., Chin, T.S., Shabbir, A., Kim, G., Crnjac, A., Samo, H., Díez del Val, I., Leturio, S., Ramón, J.M., Dal Cero, M., Rifá, S., Rico, M., Pagan Pomar, A., Martinez Corcoles, J.A., Rodicio Miravalles, J.L., Pais, S.A., Turienzo, S.A., Alvarez, L.S., Campos, P.V., Rendo, A.G., García, S.S., Santos, E.P.G., Martínez, E.T., Fernández Díaz, M.J., Magadán Álvarez, C., Concepción Martín, V., Díaz López, C., Rosat Rodrigo, A., Pérez Sánchez, L.E., Bailón Cuadrado, M., Tinoco Carrasco, C., Choolani Bhojwani, E., Sánchez, D.P., Ahmed, M.E., Dzhendov, T., Lindberg, F., Rutegård, M., Sundbom, M., Mickael, C., Colucci, N., Schnider, A., Er, S., Kurnaz, E., Turkyilmaz, S., Turkyilmaz, A., Yildirim, R., Baki, B.E., Akkapulu, N., Karahan, O., Damburaci, N., Hardwick, R., Safranek, P., Sujendran, V., Bennett, J., Afzal, Z., Shrotri, M., Chan, B., Exarchou, K., Gilbert, T., Amalesh, T., Mukherjee, D., Mukherjee, S., Wiggins, T.H., Kennedy, R., McCain, S., Harris, A., Dobson, G., Davies, N., Wilson, I., Mayo, D., Bennett, D., Young, R., Manby, P., Blencowe, N., Schiller, M., Byrne, B., Mitton, D., Wong, V., Elshaer, A., Cowen, M., Menon, V., Tan, L.C., McLaughlin, E., Koshy, R., Sharp, C., Brewer, H., Das, N., Cox, M., Al Khyatt, W., Worku, D., Iqbal, R., Walls, L., McGregor, R., Fullarton, G., Macdonald, A., MacKay, C., Craig, C., Dwerryhouse, S., Hornby, S., Jaunoo, S., Wadley, M., Baker, C., Saad, M., Kelly, M., Davies, A., Di Maggio, F., Mistry, P., Singhal, R., Tucker, O., Kapoulas, S., Powell-Brett, S., Davis, P., Bromley, G., Watson, L., Verma, R., Ward, J., Shetty, V., Ball, C., Pursnani, K., Sarela, A., Sue Ling, H., Mehta, S., Hayden, J., To, N., Palser, T., Hunter, D., Supramaniam, K., Butt, Z., Ahmed, A., Kumar, S., Chaudry, A., Moussa, O., Kordzadeh, A., Lorenzi, B., Wilson, M., Patil, P., Noaman, I., Willem, J., Bouras, G., Evans, R., Singh, M., Warrilow, H., Ahmad, A., Tewari, N., Yanni, F., Couch, J., Theophilidou, E., Reilly, J.J., van Boxel, Gijs, Akbari, K., Zanotti, D., Sgromo, B., Sanders, G., Wheatley, T., Ariyarathenam, A., Reece-Smith, A., Humphreys, L., Choh, C., Carter, N., Knight, B., Pucher, P., Athanasiou, A., Tan, B., Abdulrahman, M., Vickers, J., Akhtar, K., Chaparala, R., Brown, R., Alasmar, M.M.A., Ackroyd, R., Patel, K., Tamhankar, A., Wyman, A., Walker, R., Grace, B., Abbassi, N., Slim, N., Ioannidi, L., Blackshaw, G., Havard, T., Escofet, X., Powell, A., Owera, A., Rashid, F., Jambulingam, P., Padickakudi, J., Ben-Younes, H., Mccormack, K., Makey, I.A., Karush, M.K., Seder, C.W., Liptay, M.J., Chmielewski, G., Rosato, E.L., Berger, A.C., Zheng, R., Okolo, E., Singh, A., Scott, C.D., Weyant, M.J., Mitchell, J.D., and Griffiths, Ewen A.

Published
2024
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29. Atomic spin-controlled non-reciprocal Raman amplification of fibre-guided light

Author

Pucher, Sebastian, Liedl, Christian, Jin, Shuwei, Rauschenbeutel, Arno, and Schneeweiss, Philipp

Subjects
Quantum Physics, Physics - Atomic Physics, Physics - Optics
Abstract

In a non-reciprocal optical amplifier, gain depends on whether the light propagates forwards or backwards through the device. Typically, one requires either the magneto-optical effect, a temporal modulation, or an optical nonlinearity to break reciprocity. By contrast, here, we demonstrate non-reciprocal amplification of fibre-guided light using Raman gain provided by spin-polarized atoms that are coupled to the nanofibre waist of a tapered fibre section. The non-reciprocal response originates from the propagation direction-dependent local polarization of the nanofibre-guided mode in conjunction with polarization-dependent atom-light coupling. We show that this novel mechanism does not require an external magnetic field and that it allows us to fully control the direction of amplification via the atomic spin state. Our results may simplify the construction of complex optical networks. Moreover, suitable solid-state based quantum emitters provided, our scheme could be readily implemented in photonic integrated circuits.

Published
2021
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32. Imaging and localizing individual atoms interfaced with a nanophotonic waveguide

Author

Meng, Yijian, Liedl, Christian, Pucher, Sebastian, Rauschenbeutel, Arno, and Schneeweiss, Philipp

Subjects
Quantum Physics, Physics - Atomic Physics
Abstract

Single particle-resolved fluorescence imaging is an enabling technology in cold-atom physics. However, so far, this technique was not available for nanophotonic atom-light interfaces. Here, we image single atoms that are trapped and optically interfaced using an optical nanofiber. Near-resonant light is scattered off the atoms and imaged while counteracting heating mechanisms via degenerate Raman cooling. We detect trapped atoms within 150 ms and record image sequences of given atoms. Building on our technique, we perform two experiments which are conditioned on the number and position of the nanofiber-trapped atoms. We measure the transmission of nanofiber-guided resonant light and verify its exponential scaling in the few-atom limit, in accordance with Beer-Lambert's law. Moreover, depending on the interatomic distance, we observe interference of the fields that two simultaneously trapped atoms emit into the nanofiber. The demonstrated technique enables post-selection and possible feedback schemes and thereby opens the road towards a new generation of experiments in quantum nanophotonics., Comment: Minor corrections were implemented

Published
2020
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41. Precise Lifetime Measurement of the Cesium $5^2D_{5/2}$ State

Author

Pucher, S., Schneeweiss, P., Rauschenbeutel, A., and Dareau, A.

Subjects
Physics - Atomic Physics
Abstract

We measure the lifetime of the cesium $5^2D_{5/2}$ state using a time-resolved single-photon-counting method. We excite atoms in a hot vapor cell via an electric quadrupole transition at a wavelength of $685\,\mathrm{nm}$ and record the fluorescence of a cascade decay at a wavelength of $852\,\mathrm{nm}$. We extract a lifetime of $1353(5)\,\mathrm{ns}$ for the $5^2D_{5/2}$ state, in agreement with a recent theoretical prediction. In particular, the observed lifetime is consistent with the literature values of the polarizabilities of the cesium $6P$ states. Our measurement contributes to resolving a long-standing disagreement between a number of experimental and theoretical results., Comment: 8 pages, 6 figures, 2 tables

Published
2019
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44. Non linear time compression of clear and normal speech at high rates

Author

Valentini-Botinhao, Cassia, Wester, Mirjam, Yamagishi, Junichi, Toman, Markus, Pucher, Michael, and Schabus, Dietmar

Subjects
Electrical Engineering and Systems Science - Audio and Speech Processing
Abstract

We compare a series of time compression methods applied to normal and clear speech. First we evaluate a linear (uniform) method applied to these styles as well as to naturally-produced fast speech. We found, in line with the literature, that unprocessed fast speech was less intelligible than linearly compressed normal speech. Fast speech was also less intelligible than compressed clear speech but at the highest rate (three times faster than normal) the advantage of clear over fast speech was lost. To test whether this was due to shorter speech duration we evaluate, in our second experiments, a range of methods that compress speech and silence at different rates. We found that even when the overall duration of speech and silence is kept the same across styles, compressed normal speech is still more intelligible than compressed clear speech. Compressing silence twice as much as speech improved results further for normal speech with very little additional computational costs.

Published
2019

47. The influence of anastomotic techniques on postoperative anastomotic complications: Results of the Oesophago-Gastric Anastomosis Audit

Author

Kamarajah, S.K., Evans, R.P.T., Nepogodiev, D., Hodson, J., Bundred, J.R., Gockel, I., Gossage, J.A., Isik, A., Kidane, B., Mahendran, H.A., Negoi, I., Okonta, K.E., Sayyed, R., van Hillegersberg, R., Vohra, R.S., Wijnhoven, B.P.L., Singh, P., Griffiths, E.A., Alderson, D., Bundred, J., Gossage, J., Jefferies, B., McKay, S., Mohamed, I., Siaw-Acheampong, K., Vohra, R., Wanigasooriya, K., Whitehouse, T., Gjata, A., Moreno, J.I., Takeda, F.R., Guevara Castro, R., Harustiak, T., Bekele, A., Kechagias, A., Kennedy, A., Da Roit, A., Bagajevas, A., Azagra, J.S., Mejía-Fernández, L., El Kafsi, J., Sayyed, R.H., Sousa, M., Sampaio, A.S., Blanco, R., Wallner, B., Schneider, P.M., Hsu, P.K., Gananadha, S., Wills, V., Devadas, M., Duong, C., Talbot, M., Hii, M.W., Jacobs, R., Andreollo, N.A., Johnston, B., Darling, G., Isaza-Restrepo, A., Rosero, G., Arias-Amézquita, F., Raptis, D., Gaedcke, J., Reim, D., Izbicki, J., Egberts, J.H., Dikinis, S., Kjaer, D.W., Larsen, M.H., Achiam, M.P., Saarnio, J., Theodorou, D., Liakakos, T., Korkolis, D.P., Robb, W.B., Collins, C., Murphy, T., Reynolds, J., Tonini, V., Migliore, M., Bonavina, L., Valmasoni, M., Bardini, R., Weindelmayer, J., Terashima, M., White, R.E., Alghunaim, E., Elhadi, M., Leon-Takahashi, A.M., Medina-Franco, H., Lau, P.C., Heisterkamp, J., Rosman, C., Beban, G., Babor, R., Gordon, A., Rossaak, J.I., Pal, K.M.I., Qureshi, A.U., Naqi, S.A., Syed, A.A., Barbosa, J., Vicente, C.S., Leite, J., Freire, J., Casaca, R., Costa, R.C.T., Scurtu, R.R., Mogoanta, S.S., Bolca, C., Constantinoiu, S., Sekhniaidze, D., Bjelović, M., So, J.B.Y., Gačevski, G., Loureiro, C., Pera, M., Bianchi, A., Moreno Gijón, M., Martín Fernández, J., Trugeda Carrera, M.S., Vallve-Bernal, M., Cítores Pascual, M.A., Elmahi, S., Halldestam, I., Hedberg, J., Mönig, S., Gutknecht, S., Tez, M., Guner, A., Tirnaksiz, M.B., Colak, E., Sevinç, B., Hindmarsh, A., Khan, I., Khoo, D., Byrom, R., Gokhale, J., Wilkerson, P., Jain, P., Chan, D., Robertson, K., Iftikhar, S., Skipworth, R., Forshaw, M., Higgs, S., Nijjar, R., Viswanath, Y.K.S., Turner, P., Dexter, S., Boddy, A., Allum, W.H., Oglesby, S., Cheong, E., Beardsmore, D., Maynard, N., Berrisford, R., Mercer, S., Puig, S., Melhado, R., Kelty, C., Underwood, T., Dawas, K., Lewis, W., Al-Bahrani, A., Bryce, G., Thomas, M., Arndt, A.T., Palazzo, F., Meguid, R.A., Fergusson, J., Beenen, E., Mosse, C., Salim, J., Cheah, S., Wright, T., Cerdeira, M.P., McQuillan, P., Richardson, M., Liem, H., Spillane, J., Yacob, M., Albadawi, F., Thorpe, T., Dingle, A., Cabalag, C., Loi, K., Fisher, O.M., Ward, S., Read, M., Johnson, M., Bassari, R., Bui, H., Cecconello, I., Sallum, R.A.A., da Rocha, J.R.M., Lopes, L.R., Tercioti, V., Jr, Coelho, J.D.S., Ferrer, J.A.P., Buduhan, G., Tan, L., Srinathan, S., Shea, P., Yeung, J., Allison, F., Carroll, P., Vargas-Barato, F., Gonzalez, F., Ortega, J., Nino-Torres, L., Beltrán-García, T.C., Castilla, L., Pineda, M., Bastidas, A., Gómez-Mayorga, J., Cortés, N., Cetares, C., Caceres, S., Duarte, S., Pazdro, A., Snajdauf, M., Faltova, H., Sevcikova, M., Mortensen, P.B., Katballe, N., Ingemann, T., Morten, B., Kruhlikava, I., Ainswort, A.P., Stilling, N.M., Eckardt, J., Holm, J., Thorsteinsson, M., Siemsen, M., Brandt, B., Nega, B., Teferra, E., Tizazu, A., Kauppila, J.H., Koivukangas, V., Meriläinen, S., Gruetzmann, R., Krautz, C., Weber, G., Golcher, H., Emons, G., Azizian, A., Ebeling, M., Niebisch, S., Kreuser, N., Albanese, G., Hesse, J., Volovnik, L., Boecher, U., Reeh, M., Triantafyllou, S., Schizas, D., Michalinos, A., Balli, E., Mpoura, M., Charalabopoulos, A., Manatakis, D.K., Balalis, D., Bolger, J., Baban, C., Mastrosimone, A., McAnena, O., Quinn, A., Ó Súilleabháin, C.B., Hennessy, M.M., Ivanovski, I., Khizer, H., Ravi, N., Donlon, N., Cervellera, M., Vaccari, S., Bianchini, S., Sartarelli, l., Asti, E., Bernardi, D., Merigliano, S., Provenzano, L., Scarpa, M., Saadeh, L., Salmaso, B., De Manzoni, G., Giacopuzzi, S., La Mendola, R., De Pasqual, C.A., Tsubosa, Y., Niihara, M., Irino, T., Makuuchi, R., Ishii, K., Mwachiro, M., Fekadu, A., Odera, A., Mwachiro, E., AlShehab, D., Ahmed, H.A., Shebani, A.O., Elhadi, A., Elnagar, F.A., Elnagar, H.F., Makkai-Popa, S.T., Wong, L.F., Tan, Y.R., Thannimalai, S., Ho, C.A., Pang, W.S., Tan, J.H., Basave, H.N.L., Cortés-González, R., Lagarde, S.M., van Lanschot, J.J.B., Cords, C., Jansen, W.A., Martijnse, I., Matthijsen, R., Bouwense, S., Klarenbeek, B., Verstegen, M., van Workum, F., Ruurda, J.P., van der Sluis, P.C., de Maat, M., Evenett, N., Johnston, P., Patel, R., MacCormick, A., Young, M., Smith, B., Ekwunife, C., Memon, A.H., Shaikh, K., Wajid, A., Khalil, N., Haris, M., Mirza, Z.U., Qudus, S.B.A., Sarwar, M.Z., Shehzadi, A., Raza, A., Jhanzaib, M.H., Farmanali, J., Zakir, Z., Shakeel, O., Nasir, I., Khattak, S., Baig, M., MA, Noor, Ahmed, H.H., Naeem, A., Pinho, A.C., da Silva, R., Bernardes, A., Campos, J.C., Matos, H., Braga, T., Monteiro, C., Ramos, P., Cabral, F., Gomes, M.P., Martins, P.C., Correia, A.M., Videira, J.F., Ciuce, C., Drasovean, R., Apostu, R., Paitici, S., Racu, A.E., Obleaga, C.V., Beuran, M., Stoica, B., Ciubotaru, C., Negoita, V., Cordos, I., Birla, R.D., Predescu, D., Hoara, P.A., Tomsa, R., Shneider, V., Agasiev, M., Ganjara, I., Gunjić, D., Veselinović, M., Babič, T., Chin, T.S., Shabbir, A., Kim, G., Crnjac, A., Samo, H., Díez del Val, I., Leturio, S., Ramón, J.M., Dal Cero, M., Rifá, S., Rico, M., Pagan Pomar, A., Martinez Corcoles, J.A., Rodicio Miravalles, J.L., Pais, S.A., Turienzo, S.A., Alvarez, L.S., Campos, P.V., Rendo, A.G., García, S.S., Santos, E.P.G., Martínez, E.T., Fernández Díaz, M.J., Magadán Álvarez, C., Concepción Martín, V., Díaz López, C., Rosat Rodrigo, A., Pérez Sánchez, L.E., Bailón Cuadrado, M., Tinoco Carrasco, C., Choolani Bhojwani, E., Sánchez, D.P., Ahmed, M.E., Dzhendov, T., Lindberg, F., Rutegård, M., Sundbom, M., Mickael, C., Colucci, N., Schnider, A., Er, S., Kurnaz, E., Turkyilmaz, S., Turkyilmaz, A., Yildirim, R., Baki, B.E., Akkapulu, N., Karahan, O., Damburaci, N., Hardwick, R., Safranek, P., Sujendran, V., Bennett, J., Afzal, Z., Shrotri, M., Chan, B., Exarchou, K., Gilbert, T., Amalesh, T., Mukherjee, D., Mukherjee, S., Wiggins, T.H., Kennedy, R., McCain, S., Harris, A., Dobson, G., Davies, N., Wilson, I., Mayo, D., Bennett, D., Young, R., Manby, P., Blencowe, N., Schiller, M., Byrne, B., Mitton, D., Wong, V., Elshaer, A., Cowen, M., Menon, V., Tan, L.C., McLaughlin, E., Koshy, R., Sharp, C., Brewer, H., Das, N., Cox, M., Al Khyatt, W., Worku, D., Iqbal, R., Walls, L., McGregor, R., Fullarton, G., Macdonald, A., MacKay, C., Craig, C., Dwerryhouse, S., Hornby, S., Jaunoo, S., Wadley, M., Baker, C., Saad, M., Kelly, M., Davies, A., Di Maggio, F., Mistry, P., Singhal, R., Tucker, O., Kapoulas, S., Powell-Brett, S., Davis, P., Bromley, G., Watson, L., Verma, R., Ward, J., Shetty, V., Ball, C., Pursnani, K., Sarela, A., Sue Ling, H., Mehta, S., Hayden, J., To, N., Palser, T., Hunter, D., Supramaniam, K., Butt, Z., Ahmed, A., Kumar, S., Chaudry, A., Moussa, O., Kordzadeh, A., Lorenzi, B., Wilson, M., Patil, P., Noaman, I., Willem, J., Bouras, G., Evans, R., Singh, M., Warrilow, H., Ahmad, A., Tewari, N., Yanni, F., Couch, J., Theophilidou, E., Reilly, J.J., van Boxel Gijs, Akbari, K., Zanotti, D., Sgromo, B., Sanders, G., Wheatley, T., Ariyarathenam, A., Reece-Smith, A., Humphreys, L., Choh, C., Carter, N., Knight, B., Pucher, P., Athanasiou, A., Tan, B., Abdulrahman, M., Vickers, J., Akhtar, K., Chaparala, R., Brown, R., Alasmar, M.M.A., Ackroyd, R., Patel, K., Tamhankar, A., Wyman, A., Walker, R., Grace, B., Abbassi, N., Slim, N., Ioannidi, L., Blackshaw, G., Havard, T., Escofet, X., Powell, A., Owera, A., Rashid, F., Jambulingam, P., Padickakudi, J., Ben-Younes, H., Mccormack, K., Makey, I.A., Karush, M.K., Seder, C.W., Liptay, M.J., Chmielewski, G., Rosato, E.L., Berger, A.C., Zheng, R., Okolo, E., Singh, A., Scott, C.D., Weyant, M.J., and Mitchell, J.D.

Published
2022
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