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Quantum Coding with Low-Depth Random Circuits

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Physical Review X 2021年第3期11卷 031066-031066页

作者： Michael J. Gullans Stefan Krastanov David A. Huse Liang Jiang Steven T. Flammia Joint Center for Quantum Information and Computer Science NIST/University of Maryland College Park Maryland 20742 USA Department of Physics Princeton University Princeton New Jersey 08544 USA John A. Paulson School of Engineering and Applied Sciences Harvard University Cambridge Massachusetts 02138 USA Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA Pritzker School of Molecular Engineering The University of Chicago Illinois 60637 USA AWS Center for Quantum Computing Pasadena California 91125 USA

Random quantum circuits have played a central role in establishing the computational advantages of near-term quantum computers over their conventional counterparts. Here, we use ensembles of low-depth random circuits with local connectivity in D≥1 spatial dimensions to generate quantum error-correcting codes. For random stabilizer codes and the erasure channel, we find strong evidence that a depth O(logN) random circuit is necessary and sufficient to converge (with high probability) to zero failure probability for any finite amount below the optimal erasure threshold, set by the channel capacity, for any D. Previous results on random circuits have only shown that O(N1/D) depth suffices or that O(log3N) depth suffices for all-to-all connectivity (D→∞). We then study the critical behavior of the erasure threshold in the so-called moderate deviation limit, where both the failure probability and the distance to the optimal threshold converge to zero with N. We find that the requisite depth scales like O(logN) only for dimensions D≥2 and that random circuits require O(N) depth for D=1. Finally, we introduce an “expurgation” algorithm that uses quantum measurements to remove logical operators that cause the code to fail by turning them into either additional stabilizers or into gauge operators in a subsystem code. With such targeted measurements, we can achieve sublogarithmic depth in D≥2 spatial dimensions below capacity without increasing the maximum weight of the check operators. We find that for any rate beneath the capacity, high-performing codes with thousands of logical qubits are achievable with depth 4–8 expurgated random circuits in D=2 dimensions. These results indicate that finite-rate quantum codes are practically relevant for near-term devices and may significantly reduce the resource requirements to achieve fault tolerance for near-term applications.

关键词： Quantum channels Quantum computation Quantum error correction

Two instances of random access code in the quantum regime

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arXiv 2022年

作者： Sakharwade, Nitica Studziński, Michal Eckstein, Michal Horodecki, Pawel International Centre for Theory of Quantum Technologies University of Gdańsk Jana Bażyńskiego 1A Gdańsk80-309 Poland Perimeter Institute for Theoretical Physics Waterloo Canada Department of Physics and Astronomy University of Waterloo Waterloo Canada Institute of Theoretical Physics and Astrophysics National Quantum Information Centre in Gdańsk Faculty of Mathematics Physics and Informatics University of Gdańsk Wita Stwosza 57 Gdańsk80-952 Poland Institute of Theoretical Physics Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University ul. Lojasiewicza 11 Kraków30-348 Poland Faculty of Applied Physics and Mathematics National Quantum Information Centre Gdansk University of Technology Gabriela Narutowicza 11/12 Gdańsk80-233 Poland

We consider two classes of quantum generalisations of Random Access Code (RAC) and study the bounds for probabilities of success for such tasksa. It provides a useful framework for the study of certain information processing tasks with constrained resources. The first class is based on a random access code with quantum inputs and output known as the No-Signalling Quantum RAC (NS-QRAC) box [A. Grudka et al., Phys. Rev. A 92, 052312 (2015)], where unbounded entanglement and constrained classical communication are allowed. We show that it can be seen as quantum teleportation with constrained classical communication and provide a lower quantum bound for the success probability. We consider two modifications to the NS-QRAC scenario: The first, where unbounded entanglement and constrained quantum communication is allowed and the second, where bounded entanglement and unconstrained classical communication is allowed. We find a monogamy relation for the transmission fidelities, which - in contrast to the usual communication schemes - involves multiple senders and a single receiver. We provide an upper bounds for the latter and a lower one for the former. The second class is based on a RAC with a quantum channel and shared entanglement [A. Tavakoli et al., PRX Quantum 2, 040357 (2021)]. We study the set of tasks where two inputs made of two digits of d-base are encoded over a qudit and a maximally entangled state. We show that such tasks can be seen as quantum dense-coding with constrained quantum communication and explicit protocols, which give lower quantum bounds for the tasks' efficiency, in dimensions d = 2, 3, 4. The employed encoding utilises Gray codes. Copyright © 2022, The Authors. All rights reserved.

关键词： Quantum communication

Projective preferential Bayesian optimization

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arXiv 2020年

作者： Mikkola, Petrus Todorović, Milica Järvi, Jari Rinke, Patrick Kaski, Samuel Helsinki Institute for Information Technology HIIT Department of Computer Science Aalto University Espoo Finland Department of Applied Physics Aalto University Espoo Finland

Bayesian optimization is an effective method for finding extrema of a black-box function. We propose a new type of Bayesian optimization for learning user preferences in high-dimensional spaces. The central assumption is that the underlying objective function cannot be evaluated directly, but instead a minimizer along a projection can be queried, which we call a projective preferential query. The form of the query allows for feedback that is natural for a human to give, and which enables interaction. This is demonstrated in a user experiment in which the user feedback comes in the form of optimal position and orientation of a molecule adsorbing to a surface. We demonstrate that our framework is able to find a global minimum of a high-dimensional black-box function, which is an infeasible task for existing preferential Bayesian optimization frameworks that are based on pairwise comparisons. Copyright © 2020, The Authors. All rights reserved.

关键词： Global optimization

Experimental implementation of an efficient test of quantumness

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arXiv 2022年

作者： Lewis, Laura Zhu, Daiwei Gheorghiu, Alexandru Noel, Crystal Katz, Or Harraz, Bahaa Wang, Qingfeng Risinger, Andrew Feng, Lei Biswas, Debopriyo Egan, Laird Vidick, Thomas Cetina, Marko Monroe, Christopher Institute for Quantum Information and Matter Department of Computing and Mathematical Sciences California Institute of Technology CA91125 United States Division of Physics Mathematics and Astronomy California Institute of Technology CA91125 United States Joint Quantum Institute Departments of Physics and Electrical and Computer Engineering University of Maryland College ParkMD20742 United States Joint Center for Quantum Information and Computer Science NIST University of Maryland College ParkMD20742 United States IonQ Inc. College ParkMD20740 United States Departments of Electrical and Computer Engineering University of Maryland College ParkMD20742 United States Institute for Theoretical Studies ETH Zürich CH 8001 Switzerland Duke Quantum Center Department of Physics Duke University DurhamNC27708 United States Department of Electrical and Computer Engineering Duke University DurhamNC27708 United States Chemical Physics Program Institute for Physical Science and Technology University of Maryland College ParkMD20742 United States

A test of quantumness is a protocol where a classical user issues challenges to a quantum device to determine if it exhibits non-classical behavior, under certain cryptographic assumptions. Recent attempts to implement such tests on current quantum computers rely on either interactive challenges with efficient verification, or non-interactive challenges with inefficient (exponential time) verification. In this paper, we execute an efficient non-interactive test of quantumness on an ion-trap quantum computer. Our results significantly exceed the bound for a classical device’s success. Copyright © 2022, The Authors. All rights reserved.

关键词： Qubits

Quantum Simulation for High-Energy physics

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PRX Quantum 2023年第2期4卷 027001-027001页

作者： Christian W. Bauer Zohreh Davoudi A. Baha Balantekin Tanmoy Bhattacharya Marcela Carena Wibe A. de Jong Patrick Draper Aida El-Khadra Nate Gemelke Masanori Hanada Dmitri Kharzeev Henry Lamm Ying-Ying Li Junyu Liu Mikhail Lukin Yannick Meurice Christopher Monroe Benjamin Nachman Guido Pagano John Preskill Enrico Rinaldi Alessandro Roggero David I. Santiago Martin J. Savage Irfan Siddiqi George Siopsis David Van Zanten Nathan Wiebe Yukari Yamauchi Kübra Yeter-Aydeniz Silvia Zorzetti Physics Division Lawrence Berkeley National Laboratory Berkeley California 94720 USA Department of Physics Maryland Center for Fundamental Physics and the NSF Institute for Robust Quantum Simulation University of Maryland College Park Maryland 20742 USA Department of Physics University of Wisconsin Madison Wisconsin 53706 USA T-2 Los Alamos National Laboratory Los Alamos New Mexico 87545 USA Fermi National Accelerator Laboratory Batavia Illinois 60510 USA Enrico Fermi Institute University of Chicago Chicago Illinois 60637 USA Kavli Institute for Cosmological Physics University of Chicago Chicago Illinois 60637 USA Department of Physics University of Chicago Chicago Illinois 60637 USA Department of Physics and Illinois Center for the Advanced Study of the Universe and Illinois Quantum Information Science and Technology Center University of Illinois Urbana Illinois 61801 USA QuEra Computing Inc Boston Massachusetts 02135 USA Department of Mathematics University of Surrey Guildford Surrey GU2 7XH United Kingdom Center for Nuclear Theory Department of Physics and Astronomy Stony Brook University New York 11794-3800 USA Department of Physics Brookhaven National Laboratory Upton New York 11973 USA Peng Huanwu Center for Fundamental Theory Hefei Anhui 230026 China Interdisciplinary Center for Theoretical Study University of Science and Technology of China Hefei Anhui 230026 China Pritzker School of Molecular Engineering Chicago Quantum Exchange and Kadanoff Center for Theoretical Physics University of Chicago Illinois 60637 USA qBraid Co. Harper Court 5235 Chicago Illinois 60615 USA Department of Physics Harvard University Cambridge Massachusetts 02138 USA Department of Physics and Astronomy University of Iowa Iowa City Iowa 52242 USA Duke Quantum Center Duke University Durham North Carolina 27701 USA Department of Electrical and Computer Engineering Duke University Durham North Carolina 27708 USA Department of Physics Duke University

It is for the first time that quantum simulation for high-energy physics (HEP) is studied in the U.S. decadal particle-physics community planning, and in fact until recently, this was not considered a mainstream topic in the community. This fact speaks of a remarkable rate of growth of this subfield over the past few years, stimulated by the impressive advancements in quantum information sciences (QIS) and associated technologies over the past decade, and the significant investment in this area by the government and private sectors in the U.S. and other countries. High-energy physicists have quickly identified problems of importance to our understanding of nature at the most fundamental level, from tiniest distances to cosmological extents, that are intractable with classical computers but may benefit from quantum advantage. They have initiated, and continue to carry out, a vigorous program in theory, algorithm, and hardware co-design for simulations of relevance to the HEP mission. This Roadmap is an attempt to bring this exciting and yet challenging area of research to the spotlight, and to elaborate on what the promises, requirements, challenges, and potential solutions are over the next decade and beyond.

关键词： Quantum simulation

Nonlocality in photonic materials and metamaterials: roadmap

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Optical Materials Express 2025年第7期15卷 1544-1709页

作者： Francesco Monticone N Asger Mortensen Antonio I Fernández-Domínguez Yu Luo Xuezhi Zheng Christos Tserkezis Jacob B Khurgin Tigran V Shahbazyan André J Chaves Nuno M R Peres Gino Wegner Kurt Busch Huatian Hu Fabio Della Sala Pu Zhang Cristian Ciracì Javier Aizpurua Antton Babaze Andrei G Borisov Xue-Wen Chen Thomas Christensen Wei Yan Yi Yang Ulrich Hohenester Lorenz Huber Martijn Wubs Simone De Liberato P A D Gonçalves F Javier García de Abajo Ortwin Hess Illya Tarasenko Joel D Cox Line Jelver Eduardo J C Dias Miguel Sánchez Sánchez Dionisios Margetis Guillermo Gómez-Santos Igor M Vasilevskiy Tobias Stauber Sergei Tretyakov Constantin Simovski Samaneh Pakniyat J Sebastián Gómez-Díaz Igor V Bondarev Svend-Age Biehs Alexra Boltasseva Vladimir M Shalaev Alexey V Krasavin Anatoly V Zayats Andrea Alù Jung-Hwan Song Mark L Brongersma Uriel Levy Olivia Y Long Cheng Guo Shanhui Fan Sergey I Bozhevolnyi Adam Overvig Filipa R Prudêncio Mário G Silveirinha S Ali Hassani Gangaraj Christos Argyropoulos Paloma A Huidobro Emanuele Galiffi Fan Yang John B Pendry David A B Miller School of Electrical and Computer Engineering Cornell University Ithaca New York 14853 USA POLIMA—Center for Polariton-driven Light-Matter Interactions University of Southern Denmark Campusvej 55 DK-5230 Odense M Denmark D-IAS—Danish Institute for Advanced Study University of Southern Denmark Campusvej 55 DK-5230 Odense M Denmark Departamento de Física Teórica de la Materia Condensada Universidad Autónoma de Madrid E-28049 Madrid Spain Condensed Matter Physics Center (IFIMAC) Universidad Autónoma de Madrid E-28049 Madrid Spain School of Electrical and Electronic Engineering Nanyang Technological University Singapore 639798 Singapore Key Laboratory of Radar Imaging and Microwave Photonics Ministry of Education College of Electronic and Information Engineering Nanjing University of Aeronautics and Astronautics Nanjing 211106 China WaveCoRE Division Department of Electrical Engineering KU Leuven Leuven B-3001 Belgium Department of Electrical and Computer Engineering Johns Hopkins University Baltimore Maryland 21218 USA Department of Physics Jackson State University Jackson Mississippi 39217 USA Department of Physics Aeronautics Institute of Technology 12228-900 So Jos dos Campos SP Brazil Centro de Física (CF-UM-UP) and Departamento de Física Universidade do Minho P-4710-057 Braga Portugal International Iberian Nanotechnology Laboratory (INL) Av Mestre José Veiga 4715-330 Braga Portugal Max-Born-Institut 12489 Berlin Germany Humboldt-Universität zu Berlin Institut für Physik AG Theoretische Optik and Photonik 12489 Berlin Germany Center for Biomolecular Nanotechnologies Istituto Italiano di Tecnologia Via Barsanti 14 73010 Arnesano Italy Institute for Microelectronics and Microsystems (CNR-IMM) Via Monteroni Campus Unisalento 73100 Lecce Italy School of Physics Huazhong University of Science and Technology Luoyu Road 1037 Wuhan 430074 China Donostia International Physics Center DIPC 20018 Donostia-San Sebastián Spain Ikerbasque Basque Foundation fo

Photonic technologies continue to drive the quest for new optical materials with unprecedented responses. A major frontier in this field is the exploration of nonlocal (spatially dispersive) materials, going beyond the local, wavevector-independent assumption traditionally adopted in optical material modeling. The growing interest in plasmonic, polaritonic, and quantum materials has revealed naturally occurring nonlocalities, emphasizing the need for more accurate models to predict and design their optical responses. This has major implications also for topological, nonreciprocal, and time-varying systems based on these material platforms. Beyond natural materials, artificially structured materials—metamaterials and metasurfaces—can provide even stronger and engineered nonlocal effects, emerging from long-range interactions or multipolar effects. This is a rapidly expanding area in the field of photonic metamaterials, with open frontiers yet to be explored. In metasurfaces, in particular, nonlocality engineering has emerged as a powerful tool for designing strongly wavevector-dependent responses, enabling enhanced wavefront control, spatial compression, multifunctional devices, and wave-based computing. Furthermore, nonlocality and related concepts play a critical role in defining the ultimate limits of what is possible in optics, photonics, and wave physics. This Roadmap aims to survey the most exciting developments in nonlocal photonic materials and metamaterials, highlight new opportunities and open challenges, and chart new pathways that will drive this emerging field forward—toward new scientific discoveries and technological *** by Optica Publishing Group under the terms of the Creative Commons Attribution 4.0 License . Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

关键词： Chemical elements Localized surface plasmon resonance Material properties Near field scanning optical microscopy Optical materials Thin films

Versatile Method of Engineering the Band Alignment and the Electron Wavefunction Hybridization of Hybrid Quantum Devices

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arXiv 2023年

作者： Li, Guoan Shi, Xiaofan Lin, Ting Yang, Guang Rossi, Marco Badawy, Ghada Zhang, Zhiyuan Shi, Jiayu Qian, Degui Lu, Fang Gu, Lin Wang, An-Qi Tong, Bingbing Li, Peiling Lyu, Zhaozheng Liu, Guangtong Qu, Fanming Dou, Ziwei Pan, Dong Zhao, Jianhua Zhang, Qinghua Bakkers, Erik P.A.M. Nowak, Michal P. Wójcik, Pawel Lu, Li Shen, Jie Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing100190 China AGH University of Krakow Academic Centre for Materials and Nanotechnology al. A. Mickiewicza 30 Krakow30-059 Poland AGH University of Krakow Faculty of Physics and Applied Computer Science al. A. Mickiewicza 30 Krakow30-059 Poland Department of Applied Physics Eindhoven University of Technology Eindhoven5600 MB Netherlands State Key Laboratory of Superlattices and Microstructures Institute of Semiconductors Chinese Academy of Sciences P. O. Box 912 Beijing100083 China Beijing National Center for Electron Microscopy Laboratory of Advanced Materials Department of Materials Science and Engineering Tsinghua University Beijing100084 China School of Physical Sciences University of Chinese Academy of Sciences Beijing100049 China Songshan Lake Materials Laboratory Dongguan523808 China Beijing Academy of Quantum Information Sciences Beijing100193 China Center of Materials Science and Optoelectronics Engineering CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of Sciences Beijing100190 China

Hybrid devices that combine superconductors (S) and semiconductors (Sm) have attracted great attention due to the integration of the properties of both materials, which relies on the interface details and the resulting coupling strength and wavefunction hybridization. However until now, none of the experiments have reported good control of band alignment of the interface, as well as its tunability to the coupling and hybridization. Here, the interface is modified by inducing specific argon milling while maintaining its high-quality, e.g., atomic connection, which results in a large induced superconducting gap and ballistic transport. By comparing with Schrödinger-Poisson calculations, it is proven that this method can vary the band bending/coupling strength and the electronic spatial distribution. In the strong coupling regime, the coexistence and tunability of crossed Andreev reflection and elastic co-tunnelling—key ingredients for the Kitaev chain—are confirmed. This method is also generic for other materials and achieves a hard and huge superconducting gap in Pb-InSb devices. Such a versatile method, compatible with the standard fabrication process and accompanied by the well-controlled modification of the interface, will definitely boost the creation of more sophisticated hybrid devices for exploring physics in solid-state systems. Copyright © 2023, The Authors. All rights reserved.

关键词： III-V semiconductors

Macroscopically Self-Aligned and Chiralized Carbon Nanotubes: From Filtration to Innovation

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arXiv 2023年

作者： Doumani, Jacques Zahn, Keshav Yu, Shengjie Barrios, Gustavo Rodriguez Sasmal, Somesh Kikuchi, Rikuta Kritzell, T. Elijah Xu, Hongjing Baydin, Andrey Kono, Junichiro Department of Electrical and Computer Engineering Rice University 6100 Main Street HoustonTX77005 United States Applied Physics Graduate Program Smalley–Curl Institute Rice University 6100 Main Street HoustonTX77005 United States Carbon Hub Rice University 6100 Main Street HoustonTX77005 United States Smalley–Curl Institute Rice University 6100 Main Street HoustonTX77005 United States Department of Physics and Astronomy Rice University 6100 Main Street HoustonTX77005 United States Department of Materials Science and NanoEngineering Rice University 6100 Main Street HoustonTX77005 United States

Because of their natural one-dimensional (1D) structure combined with intricate chiral variations, carbon nanotubes (CNTs) exhibit various exceptional physical properties, such as ultrahigh electrical and thermal conductivity, exceptional mechanical strength, and chirality-dependent metallicity. These properties make CNTs highly promising for diverse applications, including field-effect transistors, sensors, photodetectors, and thermoelectric devices. While CNTs excel individually at the nanoscale, their 1D and chiral nature can be lost on a macroscopic scale when they are randomly assembled. Therefore, the alignment and organization of CNTs in macroscopic structures is crucial for harnessing their full potential. In this review, we explore recent advancements in understanding CNT alignment mechanisms, improving CNT aligning methods, and demonstrating macroscopically 1D properties of ordered CNT assemblies. We also focus on a newly discovered class of CNT architectures, combining CNT alignment and twisting mechanisms to create artificial radial and chiral CNT films at wafer scales. Finally, we summarize recent developments related to aligned and chiral CNT films in optoelectronics, highlighting their unique roles in solar cells, thermal emitters, and optical modulators. Copyright © 2023, The Authors. All rights reserved.

关键词： Carbon nanotubes

CloudBrain-MRS: An Intelligent Cloud Computing Platform for in vivo Magnetic Resonance Spectroscopy Preprocessing, Quantification, and Analysis

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arXiv 2023年

作者： Chen, Xiaodie Li, Jiayu Chen, Dicheng Zhou, Yirong Tu, Zhangren Lin, Meijin Kang, Taishan Lin, Jianzhong Gong, Tao Zhu, Liuhong Zhou, Jianjun Ou-Yang, Lin Guo, Jiefeng Dong, Jiyang Guo, Di Qu, Xiaobo Department of Electronic Science Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance Xiamen University Xiamen China Department of Applied Marine Physics & Engineering Xiamen University Xiamen China Department of Radiology Zhongshan Hospital Affiliated to Xiamen University Xiamen China Departments of Radiology Shandong Provincial Hospital Affiliated to Shandong First Medical University Shandong Jinan China Fudan University Xiamen China Department of Medical Imaging of Southeast Hospital Medical College of Xiamen University Xiamen China Department of Microelectronics and Integrated Circuit Xiamen University Xiamen China School of Computer and Information Engineering Xiamen University of Technology Xiamen China

Magnetic resonance spectroscopy (MRS) is an important clinical imaging method for diagnosis of diseases. MRS spectrum is used to observe the signal intensity of metabolites or further infer their concentrations. Although the magnetic resonance vendors commonly provide basic functions of spectra plots and metabolite quantification, the widespread clinical research of MRS is still limited due to the lack of easy-to-use processing software or platform. To address this issue, we have developed CloudBrain-MRS, a cloud-based online platform that provides powerful hardware and advanced algorithms. The platform can be accessed simply through a web browser, without the need of any program installation on the user side. CloudBrain-MRS also integrates the classic LCModel and advanced artificial intelligence algorithms and supports batch preprocessing, quantification, and analysis of MRS data from different vendors. Additionally, the platform offers useful functions: 1) Automatically statistical analysis to find biomarkers for diseases;2) Consistency verification between the classic and artificial intelligence quantification algorithms;3) Colorful three-dimensional visualization for easy observation of individual metabolite spectrum. Last, both healthy and mild cognitive impairment patient data are used to demonstrate the functions of the platform. To the best of our knowledge, this is the first cloud computing platform for in vivo MRS with artificial intelligence processing. We have shared our cloud platform at MRSHub, providing free access and service for two years. Please visit https://***/software_all/#CloudBrain-MRS or https://***/***. Copyright © 2023, The Authors. All rights reserved.

关键词： Magnetic resonance spectroscopy