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Modular Average and Weyl Anomaly in Two-Dimensional Schwarzian Theory

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arXiv 2023年

作者： Huang, Xing Ma, Chen-Te Institute of Modern Physics Northwest University Xi’an710069 China NSFC-SPTP Peng Huanwu Center for Fundamental Theory Xi’an710127 China Shaanxi Key Laboratory for Theoretical Physics Frontiers Xi’an710069 China Department of Physics and Astronomy Iowa State University AmesIA50011 United States Asia Pacific Center for Theoretical Physics Pohang University of Science and Technology Gyeongsangbuk-do Pohang37673 Korea Republic of Guangdong Provincial Key Laboratory of Nuclear Science Institute of Quantum Matter South China Normal University Guangdong Guangzhou510006 China School of Physics and Telecommunication Engineering South China Normal University Guangdong Guangzhou510006 China Guangdong-Hong Kong Joint Laboratory of Quantum Matter Southern Nuclear Science Computing Center South China Normal University Guangdong Guangzhou510006 China The Laboratory for Quantum Gravity and Strings Department of Mathematics and Applied Mathematics University of Cape Town Private Bag Rondebosch7700 South Africa

The gauge formulation of Einstein gravity in AdS3 background leads to a boundary theory that breaks modular symmetry and loses the covariant form. We examine the Weyl anomaly for the cylinder and torus manifolds. The divergent term is the same as the Liouville theory when transforming from the cylinder to the sphere. The general Weyl transformation on the torus also reproduces the Liouville theory. The Weyl transformation introduces an additional boundary term for reproducing the Liouville theory, which allows the use of CFT techniques to analyze the theory. The torus partition function in this boundary theory is one-loop exact, and an analytical solution to disjoint two-interval Rényi-2 mutual information can be obtained. We also discuss a first-order phase transition for the separation length of two intervals, which occurs at the classical level but is smoothed out by non-perturbative effects captured by averaging over a modular group in the boundary theory. Copyright © 2023, The Authors. All rights reserved.

关键词： Cylinders (shapes)

QPSO-CD: quantum-behaved particle swarm optimization algorithm with Cauchy distribution

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arXiv 2020年

作者： Bhatia, Amandeep Singh Saggi, Mandeep Kaur Zheng, Shenggen Nayak, Soumya Ranjan Chitkara University Institute of Engineering & Technology Chitkara University Punjab India Department of Computer Science Thapar Institute of Engineering & Technology India Center for Quantum Computing Peng Cheng Laboratory Shenzhen China Amity School Of Engineering & Technology Amity University Uttar Pradesh Noida India

Motivated by the particle swarm optimization (PSO) and quantum computing theory, we have presented a quantum variant of PSO (QPSO) mutated with Cauchy operator and natural selection mechanism (QPSO-CD) from evolutionary computations. The performance of proposed hybrid quantum-behaved particle swarm optimization with Cauchy distribution (QPSO-CD) is investigated and compared with its counterparts based on a set of benchmark problems. Moreover, QPSO-CD is employed in well-studied constrained engineering problems to investigate its applicability. Further, the correctness and time complexity of QPSO-CD are analysed and compared with the classical PSO. It has been proved that QPSO-CD handles such real-life problems efficiently and can attain superior solutions in most of the problems. The experimental results shown that QPSO associated with Cauchy distribution and natural selection strategy outperforms other variants in context of stability and convergence. Copyright © 2020, The Authors. All rights reserved.

关键词： Particle swarm optimization (PSO)

Undoped Strained Ge quantum Well with Ultrahigh Mobility Grown by Reduce Pressure Chemical Vapor Deposition

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arXiv 2022年

作者： Kong, Zhenzhen Li, Zonghu Cao, Gang Su, Jiale Zhang, Yiwen Liu, Jinbiao Liu, Jingxiong Ren, Yuhui Wei, Laiming Guo, Guoping Wu, Yuanyuan Radamson, Henry H. Li, Junfeng Wu, Zhenhua Li, Haiou Yang, Jiecheng Zhao, Chao Wang, Guilei Integrated Circuit Advanced Process R&D Center Institute of Microelectronics Chinese Academy of Sciences Beijing100029 China School of Integrated Circuits University of Chinese Academy of Sciences Beijing100049 China CAS Key Laboratory of Quantum Information University of Science and Technology of China Hefei230026 China Hefei National Laboratory Hefei230088 China School of Advanced Manufacturing Engineering Hefei University Hefei230601 China Origin Quantum Computing Company Limited Hefei230026 China Research and Development Center of Optoelectronic Hybrid IC Guangdong Greater Bay Area Institute of Integrated Circuit and System Guangzhou510535 China Beijing Superstring Academy of Memory Technology 100176 China

We fabricate an undoped Ge quantum well under a 30 nm relaxed Ge0.8Si0.2 shallow barrier. The bottom barrier contains Ge0.8Si0.2 (650 ℃) followed by Ge0.9Si0.1 (800 ℃) such that variation of Ge content forms a sharp interface that can suppress the threading dislocation density (TDD) penetrating into the undoped Ge quantum well. The Ge0.8Si0.2 barrier introduces enough in-plane parallel strain (Ε strain -0.41%) in the Ge quantum well. The heterostructure field-effect transistors with a shallow buried channel obtain an ultrahigh two-dimensional hole gas (2DHG) mobility over 2×106 cm2/Vs and a very low percolation of 5.625 × 1010cm−2. A tunable fractional quantum Hall effect at high densities and high magnetic fields has also been observed. This approach defines strained germanium as providing the material basis for tuning the spin-orbit coupling strength for fast and coherent quantum *** Codes 81-05, 81V70 © 2022, CC BY-NC-ND.

关键词： Germanium

Application of the Resource Theory of Channels to Communication Scenarios

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Physical Review Letters 2020年第12期124卷 120502-120502页

作者： Ryuji Takagi Kun Wang Masahito Hayashi Center for Theoretical Physics and Department of Physics Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA Shenzhen Institute for Quantum Science and Engineering Southern University of Science and Technology Shenzhen 518055 China Center for Quantum Computing Peng Cheng Laboratory Shenzhen 518000 China Graduate School of Mathematics Nagoya University Nagoya 464-8602 Japan Centre for Quantum Technologies National University of Singapore 3 Science Drive 2 117542 Singapore

We introduce a resource theory of channels relevant to communication via quantum channels, in which the set of constant channels—useless channels for communication tasks—are considered as free resources. We find that our theory with such a simple structure is useful to address central problems in quantum Shannon theory—in particular, we provide a converse bound for the one-shot nonsignaling assisted classical capacity that naturally leads to its strong converse property, as well as obtain the one-shot channel simulation cost with nonsignaling assistance. We clarify an intimate connection between the nonsignaling assistance and our formalism by identifying the nonsignaling assisted channel coding with the channel transformation under the maximal set of resource nongenerating superchannels, providing a physical characterization of the latter. Our results provide new perspectives and concise arguments to those problems, connecting the recently developed fields of resource theories to “classic” settings in quantum information theory and shedding light on the validity of resource theories of channels as effective tools to address practical problems.

关键词： quantum channels quantum communication quantum entanglement Resource theories

First-step experiment for sensitivity improvement of DECIGO: Sensitivity optimization for simulated quantum noise by completing the square

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Physical Review D 2023年第2期107卷 022007-022007页

作者： Tomohiro Ishikawa Yuki Kawasaki Kenji Tsuji Rika Yamada Izumi Watanabe Bin Wu Shoki Iwaguchi Ryuma Shimizu Kurumi Umemura Koji Nagano Yutaro Enomoto Kentaro Komori Yuta Michimura Akira Furusawa Seiji Kawamura Department of Physics Nagoya University Nagoya Aichi 464-8602 Japan Institute of Space and Astronautical Science Japan Aerospace Exploration Agency Sagamihara Kanagawa 252-5210 Japan Department of Applied Physics School of Engineering The University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo 113-8656 Japan Department of Physics University of Tokyo Bunkyo Tokyo 113-0033 Japan LIGO Laboratory California Institute of Technology Pasadena California 91125 USA Research Center for the Early Universe (RESCEU) Graduate School of Science University of Tokyo Bunkyo Tokyo 113-0033 Japan Center for Quantum Computing RIKEN 2-1 Hirosawa Wako Saitama 351-0198 Japan The Kobayashi-Maskawa Institute for the Origin of Particles and the Universe Nagoya University Nagoya Aichi 464-8602 Japan

Decihertz Interferometer Gravitational Wave Observatory (DECIGO) is a future mission for a space-borne laser interferometer. DECIGO has 1000-km-long arm cavities mainly to detect the primordial gravitational waves (PGWs) at lower frequencies around 0.1 Hz. Observations in the electromagnetic spectrum have lowered the bounds on the upper limit of PGWs energy density (Ωgw∼10−15→10−16). As a result, DECIGO’s target sensitivity, which is mainly limited by quantum noise, needs further improvement. To maximize the feasibility of detection while constrained by DECIGO’s large diffraction loss, a quantum locking technique with an optical spring was theoretically proposed to improve the signal-to-noise ratio of the PGWs. In this paper, we experimentally verify one key element used in the theory: sensitivity optimization by completing the square of multiple detector outputs. This experiment is operated on a simplified tabletop optical setup with classical noise simulating quantum noise. We succeed in getting the best of the sensitivities with two different laser powers by the square completion method.

关键词： Gravitational wave detection Gravitational wave detectors

Finite block length analysis on quantum coherence distillation and incoherent randomness extraction

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arXiv 2020年

作者： Hayashi, Masahito Fang, Kun Wang, Kun Graduate School of Mathematics Nagoya University Nagoya464-8602 Japan Shenzhen Institute for Quantum Science and Engineering Southern University of Science and Technology Shenzhen518055 China Center for Quantum Computing Peng Cheng Laboratory Shenzhen518000 China Centre for Quantum Technologies National University of Singapore 3 Science Drive 2 117542 Singapore Institute for Quantum Computing University of Waterloo WaterlooONN2L 3G1 Canada Institute for Quantum Computing Baidu Research Beijing100193 China

We give the first systematic study on the second order asymptotics of the operational task of coherence distillation with and without assistance. In the unassisted setting, we introduce a variant of randomness extraction framework where free incoherent operations are allowed before the incoherent measurement and the randomness extractors. We then show that the maximum number of random bits extractable from a given quantum state is precisely equal to the maximum number of coherent bits that can be distilled from the same state. This relation enables us to derive tight second order expansions of both tasks in the independent and identically distributed setting. Remarkably, the incoherent operation classes that can empower coherence distillation for generic states all admit the same second order expansions, indicating their operational equivalence for coherence distillation in both asymptotic and large block length regime. We then generalize the above line of research to the assisted setting, arising naturally in bipartite quantum systems where Bob distills coherence from the state at hand, aided by the benevolent Alice possessing the other system. More precisely, we introduce a new assisted incoherent randomness extraction task and establish an exact relation between this task and the assisted coherence distillation. This strengthens the one-shot relation in the unassisted setting and confirms that this cryptographic framework indeed offers a new perspective to the study of quantum coherence distillation. Likewise, this relation yields second order characterizations to the assisted tasks. As by-products, we show the strong converse property of the aforementioned tasks from their second order expansions. Copyright © 2020, The Authors. All rights reserved.

关键词： Random processes

quantum computing for High-Energy Physics: State of the Art and Challenges

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PRX quantum 2024年第3期5卷 037001-037001页

作者： Alberto Di Meglio Karl Jansen Ivano Tavernelli Constantia Alexandrou Srinivasan Arunachalam Christian W. Bauer Kerstin Borras Stefano Carrazza Arianna Crippa Vincent Croft Roland de Putter Andrea Delgado Vedran Dunjko Daniel J. Egger Elias Fernández-Combarro Elina Fuchs Lena Funcke Daniel González-Cuadra Michele Grossi Jad C. Halimeh Zoë Holmes Stefan Kühn Denis Lacroix Randy Lewis Donatella Lucchesi Miriam Lucio Martinez Federico Meloni Antonio Mezzacapo Simone Montangero Lento Nagano Vincent R. Pascuzzi Voica Radescu Enrique Rico Ortega Alessandro Roggero Julian Schuhmacher Joao Seixas Pietro Silvi Panagiotis Spentzouris Francesco Tacchino Kristan Temme Koji Terashi Jordi Tura Cenk Tüysüz Sofia Vallecorsa Uwe-Jens Wiese Shinjae Yoo Jinglei Zhang 1211 Geneva Switzerland CQTA Computation-based Science and Technology Research Center 8803 Rüschlikon Switzerland Department of Physics IBM Quantum Physics Division Deutsches Elektronen-Synchrotron (DESY) Notkestraße 85 22607 Hamburg Germany Templergraben 55 52062 Aachen Germany TIF Lab Dipartimento di Fisica Institut für Physik 〈aQa Physics Division Department of Computer Science Facultad de Ciencias Institute of Theoretical Physics 38116 Braunschweig Germany Transdisciplinary Research Area “Building Blocks of Matter and Fundamental Interactions” (TRA Matter) and Helmholtz Institute for Radiation and Nuclear Physics (HISKP) Institute for Theoretical Physics 6020 Innsbruck Austria Department of Physics and Arnold Sommerfeld Center for Theoretical Physics Munich Germany Institute of Physics CNRS/IN2P3 IJCLab Department of Physics and Astronomy Via Marzolo 8 35131 Padua Italy Science Park 105 1098 XG Amsterdam Netherlands Department of Gravitational Waves and Fundamental Physics International Center for Elementary Particle Physics Department of Physical Chemistry 20018 Donostia–San Sebastián Spain EHU Quantum Center University of the Basque Country UPV/EHU P.O. Box 644 48080 Bilbao Spain Basque Foundation for Science Via Sommarive 14 38123 Povo Trento Italy Department Física Center of Physics and Engineering of Advanced Materials (CeFEMA) Instituto Superior Técnico Lisbon Portugal Laboratory of Physics for Materials and Emergent Technologies (LaPMET) Lisbon Portugal Kirk and Pine Street Batavia Illinois 60510 USA Albert Einstein Center for Fundamental Physics Institute for Theoretical Physics 98 Rochester Sreet Upton New York 11973 USA Institute for Quantum Computing Department of Physics and Astronomy University of Waterloo Waterloo Ontario N2L 3G1 Canada

quantum computers offer an intriguing path for a paradigmatic change of computing in the natural sciences and beyond, with the potential for achieving a so-called quantum advantage—namely, a significant (in some cases exponential) speedup of numerical simulations. The rapid development of hardware devices with various realizations of qubits enables the execution of small-scale but representative applications on quantum computers. In particular, the high-energy physics community plays a pivotal role in accessing the power of quantum computing, since the field is a driving source for challenging computational problems. This concerns, on the theoretical side, the exploration of models that are very hard or even impossible to address with classical techniques and, on the experimental side, the enormous data challenge of newly emerging experiments, such as the upgrade of the Large Hadron Collider. In this Roadmap paper, led by CERN, DESY, and IBM, we provide the status of high-energy physics quantum computations and give examples of theoretical and experimental target benchmark applications, which can be addressed in the near future. Having in mind hardware with about 100 qubits capable of executing several thousand two-qubit gates, where possible, we also provide resource estimates for the examples given using error-mitigated quantum computing. The ultimate declared goal of this task force is therefore to trigger further research in the high-energy physics community to develop interesting use cases for demonstrations on near-term quantum computers.

关键词： quantum computation quantum simulation

quantum Games and Interactive Tools for quantum Technologies Outreach and Education

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arXiv 2022年

作者： Seskir, Zeki C. Migdal, Piotr Weidner, Carrie Anupam, Aditya Case, Nicky Davis, Noah Decaroli, Chiara Ercan, İlke Foti, Caterina Gora, Pawel Jankiewicz, Klementyna La Cour, Brian R. Malo, Jorge Yago Maniscalco, Sabrina Naeemi, Azad Nita, Laurentiu Parvin, Nassim Scafirimuto, Fabio Sherson, Jacob F. Surer, Elif Wootton, James Yeh, Lia Zabello, Olga Chiofalo, Marilù Karlsruhe Institute of Technology ITAS Karlstraße 11 Karlsruhe76133 Germany Quantum Flytrap ul. Ceglowska 29 Warsaw01-809 Poland Quantum Engineering Technology Laboratories H.H. Wills Physics Laboratory Department of Electrical and Electronic Engineering University of Bristol BristolBS8 1FD United Kingdom Georgia Institute of Technology School of Literature Media and Communication 686 Cherry St NW AtlantaGA30313 United States The University of Texas at Austin Center for Quantum Research Applied Research Laboratories 10000 Burnet Rd AustinTX78758 United States National Quantum Computing Center Oxfordshire DidcotOX11 0GD United Kingdom TU Delft Department of Microelectronics Mekelweg 4 Delft2628 CD Netherlands QPlayLearn Aalto University InstituteQ - The Finnish Quantum Institute Department of Applied Physics AaltoFI-00076 11000 Finland Quantum AI Foundation Sanocka 9/103 Warsaw02-110 Poland University of Pisa Department of Physics Largo Bruno Pontecorvo 3 PisaI-56126 Italy University of Helsinki InstituteQ - The Finnish Quantum Institute Department of Physics Helsinki Finland Georgia Institute of Technology School of Electrical and Computer Engineering 777 Atlantic Drive NW AtlantaGA30332 United States Quarks Interactive Strada Bailor 93a Miercurea-Ciuc Harghita4500 Romania IBM Quantum IBM Research - Zurich Säumerstrasse 4 Rüschlikon8803 Switzerland ScienceAtHome Fuglesangs Allé 4 Aarhus8210 Denmark Aarhus University Institute for Physics and Astronomy Ny Munkegade 120 Aarhus8000 Denmark Middle East Technical University Graduate School of Informatics Department of Modeling and Simulation Üniversiteler Mah. Dumlupınar Blv. No:1 Ankara06800 Turkey University of Oxford Department of Computer Science Wolfson Building Parks Road OxfordOX1 3QD United Kingdom IBM Quantum IBM T. J. Watson Research Center Yorktown HeightsNY10598 United States Offenburg University of Applied Sciences Department of Business and Industrial Eng

In this article, we provide an extensive overview of a wide range of quantum games and interactive tools that have been employed by the community in recent years. The paper presents selected tools, as described by their developers. The list includes Hello quantum, Hello Qiskit, Particle in a Box, Psi and Delta, QPlayLearn, Virtual Lab by quantum Flytrap, quantum Odyssey, ScienceAtHome, and The Virtual quantum Optics Laboratory. Additionally, we present events for quantum game development: hackathons, game jams, and semester projects. Furthermore, we discuss the quantum Technologies Education for Everyone (QUTE4E) pilot project, which illustrates an effective integration of these interactive tools with quantum outreach and education activities. Finally, we aim at providing guidelines for incorporating quantum games and interactive tools in pedagogic materials to make quantum technologies more accessible for a wider population. Copyright © 2022, The Authors. All rights reserved.

关键词： quantum optics

Generating Approximate Ground States of Molecules Using quantum Machine Learning

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arXiv 2022年

作者： Ceroni, Jack Stetina, Torin F. Kieferová, Mária Marrero, Carlos Ortiz Arrazola, Juan Miguel Wiebe, Nathan Xanadu TorontoONM5G 2C8 Canada Department of Mathematics University of Toronto TorontoONM5S 3E1 Canada Simons Institute for the Theory of Computing BerkeleyCA94704 United States Berkeley Quantum Information and Computation Center University of California BerkeleyCA94720 United States Centre for Quantum Computation and Communication Technology Centre for Quantum Software and Information University of Technology SydneyNSW2007 Australia AI & Data Analytics Division Pacific Northwest National Laboratory RichlandWA99354 United States Department of Electrical & Computer Engineering North Carolina State University RaleighNC27607 United States Department of Computer Science University of Toronto ONM5S 1A1 Canada High Performance Computing Group Pacific Northwest National Laboratory RichlandWA99354 United States

The potential energy surface (PES) of molecules with respect to their nuclear positions is a primary tool in understanding chemical reactions from first principles. However, obtaining this information is complicated by the fact that sampling a large number of ground states over a high-dimensional PES can require a vast number of state preparations. In this work, we propose using a generative quantum machine learning model to prepare quantum states at arbitrary points on the PES. The model is trained using quantum data consisting of ground-state wavefunctions associated with different classical nuclear coordinates. Our approach uses a classical neural network to convert the nuclear coordinates of a molecule into quantum parameters of a variational quantum circuit. The model is trained using a fidelity loss function to optimize the neural network parameters. We show that gradient evaluation is efficient and numerically demonstrate our method’s ability to prepare wavefunctions on the PES of hydrogen chains, water, and beryllium hydride. In all cases, we find that a small number of training points are needed to achieve very high overlap with the groundstates in practice. From a theoretical perspective, we further prove limitations on these protocols by showing that if we were able to learn across an avoided crossing using a small number of samples, then we would be able to violate Grover’s lower bound. Additionally, we prove lower bounds on the amount of quantum data needed to learn a locally optimal neural network function using arguments from quantum Fisher information. This work further identifies that quantum chemistry can be an important use case for quantum machine learning. © 2022, CC BY.

关键词： Molecules