1
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Zhang G, Hong C, Alkalay T, Umansky V, Heiblum M, Gornyi I, Gefen Y. Measuring statistics-induced entanglement entropy with a Hong-Ou-Mandel interferometer. Nat Commun 2024; 15:3428. [PMID: 38654002 PMCID: PMC11039745 DOI: 10.1038/s41467-024-47335-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 03/26/2024] [Indexed: 04/25/2024] Open
Abstract
Despite its ubiquity in quantum computation and quantum information, a universally applicable definition of quantum entanglement remains elusive. The challenge is further accentuated when entanglement is associated with other key themes, e.g., quantum interference and quantum statistics. Here, we introduce two novel motifs that characterize the interplay of entanglement and quantum statistics: an 'entanglement pointer' and a 'statistics-induced entanglement entropy'. The two provide a quantitative description of the statistics-induced entanglement: (i) they are finite only in the presence of quantum entanglement underlined by quantum statistics and (ii) their explicit form depends on the quantum statistics of the particles (e.g., fermions, bosons, and anyons). We have experimentally implemented these ideas by employing an electronic Hong-Ou-Mandel interferometer fed by two highly diluted electron beams in an integer quantum Hall platform. Performing measurements of auto-correlation and cross-correlation of current fluctuations of the scattered beams (following 'collisions'), we quantify the statistics-induced entanglement by experimentally accessing the entanglement pointer and the statistics-induced entanglement entropy. Our theoretical and experimental approaches pave the way to study entanglement in various correlated platforms, e.g., those involving anyonic Abelian and non-Abelian states.
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Affiliation(s)
- Gu Zhang
- Beijing Academy of Quantum Information Sciences, Beijing, China
- Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Changki Hong
- Braun Center for Submicron Research, Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Tomer Alkalay
- Braun Center for Submicron Research, Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Vladimir Umansky
- Braun Center for Submicron Research, Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Moty Heiblum
- Braun Center for Submicron Research, Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel.
| | - Igor Gornyi
- Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, Karlsruhe, Germany.
| | - Yuval Gefen
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel.
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2
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Holewa P, Vajner DA, Zięba-Ostój E, Wasiluk M, Gaál B, Sakanas A, Burakowski M, Mrowiński P, Krajnik B, Xiong M, Yvind K, Gregersen N, Musiał A, Huck A, Heindel T, Syperek M, Semenova E. High-throughput quantum photonic devices emitting indistinguishable photons in the telecom C-band. Nat Commun 2024; 15:3358. [PMID: 38637520 PMCID: PMC11026509 DOI: 10.1038/s41467-024-47551-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 04/05/2024] [Indexed: 04/20/2024] Open
Abstract
Single indistinguishable photons at telecom C-band wavelengths are essential for quantum networks and the future quantum internet. However, high-throughput technology for single-photon generation at 1550 nm remained a missing building block to overcome present limitations in quantum communication and information technologies. Here, we demonstrate the high-throughput fabrication of quantum-photonic integrated devices operating at C-band wavelengths based on epitaxial semiconductor quantum dots. Our technique enables the deterministic integration of single pre-selected quantum emitters into microcavities based on circular Bragg gratings. Respective devices feature the triggered generation of single photons with ultra-high purity and record-high photon indistinguishability. Further improvements in yield and coherence properties will pave the way for implementing single-photon non-linear devices and advanced quantum networks at telecom wavelengths.
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Affiliation(s)
- Paweł Holewa
- Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, 50-370, Wrocław, Poland.
- DTU Electro, Department of Electrical and Photonics Engineering, Technical University of Denmark, Ørsteds Plads 343, DK-2800, Kongens Lyngby, Denmark.
- NanoPhoton - Center for Nanophotonics, Technical University of Denmark, Ørsteds Plads 345A, DK-2800, Kongens Lyngby, Denmark.
| | - Daniel A Vajner
- Institute of Solid State Physics, Technische Universität Berlin, 10623, Berlin, Germany
| | - Emilia Zięba-Ostój
- Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, 50-370, Wrocław, Poland
| | - Maja Wasiluk
- Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, 50-370, Wrocław, Poland
| | - Benedek Gaál
- DTU Electro, Department of Electrical and Photonics Engineering, Technical University of Denmark, Ørsteds Plads 343, DK-2800, Kongens Lyngby, Denmark
| | - Aurimas Sakanas
- DTU Electro, Department of Electrical and Photonics Engineering, Technical University of Denmark, Ørsteds Plads 343, DK-2800, Kongens Lyngby, Denmark
| | - Marek Burakowski
- Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, 50-370, Wrocław, Poland
| | - Paweł Mrowiński
- Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, 50-370, Wrocław, Poland
| | - Bartosz Krajnik
- Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, 50-370, Wrocław, Poland
| | - Meng Xiong
- DTU Electro, Department of Electrical and Photonics Engineering, Technical University of Denmark, Ørsteds Plads 343, DK-2800, Kongens Lyngby, Denmark
- NanoPhoton - Center for Nanophotonics, Technical University of Denmark, Ørsteds Plads 345A, DK-2800, Kongens Lyngby, Denmark
| | - Kresten Yvind
- DTU Electro, Department of Electrical and Photonics Engineering, Technical University of Denmark, Ørsteds Plads 343, DK-2800, Kongens Lyngby, Denmark
- NanoPhoton - Center for Nanophotonics, Technical University of Denmark, Ørsteds Plads 345A, DK-2800, Kongens Lyngby, Denmark
| | - Niels Gregersen
- DTU Electro, Department of Electrical and Photonics Engineering, Technical University of Denmark, Ørsteds Plads 343, DK-2800, Kongens Lyngby, Denmark
| | - Anna Musiał
- Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, 50-370, Wrocław, Poland
| | - Alexander Huck
- Center for Macroscopic Quantum States (bigQ), Department of Physics, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
| | - Tobias Heindel
- Institute of Solid State Physics, Technische Universität Berlin, 10623, Berlin, Germany
| | - Marcin Syperek
- Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, 50-370, Wrocław, Poland.
| | - Elizaveta Semenova
- DTU Electro, Department of Electrical and Photonics Engineering, Technical University of Denmark, Ørsteds Plads 343, DK-2800, Kongens Lyngby, Denmark.
- NanoPhoton - Center for Nanophotonics, Technical University of Denmark, Ørsteds Plads 345A, DK-2800, Kongens Lyngby, Denmark.
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3
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Regula B, Lami L. Reversibility of quantum resources through probabilistic protocols. Nat Commun 2024; 15:3096. [PMID: 38632233 PMCID: PMC11024169 DOI: 10.1038/s41467-024-47243-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 03/26/2024] [Indexed: 04/19/2024] Open
Abstract
Among the most fundamental questions in the manipulation of quantum resources such as entanglement is the possibility of reversibly transforming all resource states. The key consequence of this would be the identification of a unique entropic resource measure that exactly quantifies the limits of achievable transformation rates. Remarkably, previous results claimed that such asymptotic reversibility holds true in very general settings; however, recently those findings have been found to be incomplete, casting doubt on the conjecture. Here we show that it is indeed possible to reversibly interconvert all states in general quantum resource theories, as long as one allows protocols that may only succeed probabilistically. Although such transformations have some chance of failure, we show that their success probability can be ensured to be bounded away from zero, even in the asymptotic limit of infinitely many manipulated copies. As in previously conjectured approaches, the achievability here is realised through operations that are asymptotically resource non-generating, and we show that this choice is optimal: smaller sets of transformations cannot lead to reversibility. Our methods are based on connecting the transformation rates under probabilistic protocols with strong converse rates for deterministic transformations, which we strengthen into an exact equivalence in the case of entanglement distillation.
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Affiliation(s)
- Bartosz Regula
- Mathematical Quantum Information RIKEN Hakubi Research Team, RIKEN Cluster for Pioneering Research (CPR) and RIKEN Center for Quantum Computing (RQC), Wako, Saitama, 351-0198, Japan.
| | - Ludovico Lami
- QuSoft, Science Park 123, Amsterdam, 1098 XG, The Netherlands.
- Korteweg-de Vries Institute for Mathematics, University of Amsterdam, Science Park 105-107, Amsterdam, 1098 XG, The Netherlands.
- Institute for Theoretical Physics, University of Amsterdam, Science Park 904, Amsterdam, 1098 XH, The Netherlands.
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4
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Villegas-Aguilar L, Polino E, Ghafari F, Quintino MT, Laverick KT, Berkman IR, Rogge S, Shalm LK, Tischler N, Cavalcanti EG, Slussarenko S, Pryde GJ. Nonlocality activation in a photonic quantum network. Nat Commun 2024; 15:3112. [PMID: 38600084 PMCID: PMC11006907 DOI: 10.1038/s41467-024-47354-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 03/28/2024] [Indexed: 04/12/2024] Open
Abstract
Bell nonlocality refers to correlations between two distant, entangled particles that challenge classical notions of local causality. Beyond its foundational significance, nonlocality is crucial for device-independent technologies like quantum key distribution and randomness generation. Nonlocality quickly deteriorates in the presence of noise, and restoring nonlocal correlations requires additional resources. These often come in the form of many instances of the input state and joint measurements, incurring a significant resource overhead. Here, we experimentally demonstrate that single copies of Bell-local states, incapable of violating any standard Bell inequality, can give rise to nonlocality after being embedded into a quantum network of multiple parties. We subject the initial entangled state to a quantum channel that broadcasts part of the state to two independent receivers and certify the nonlocality in the resulting network by violating a tailored Bell-like inequality. We obtain these results without making any assumptions about the prepared states, the quantum channel, or the validity of quantum theory. Our findings have fundamental implications for nonlocality and enable the practical use of nonlocal correlations in real-world applications, even in scenarios dominated by noise.
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Affiliation(s)
- Luis Villegas-Aguilar
- Centre for Quantum Dynamics and Centre for Quantum Computation and Communication Technology, Griffith University, Yuggera Country, Brisbane, QLD, 4111, Australia
| | - Emanuele Polino
- Centre for Quantum Dynamics and Centre for Quantum Computation and Communication Technology, Griffith University, Yuggera Country, Brisbane, QLD, 4111, Australia
| | - Farzad Ghafari
- Centre for Quantum Dynamics and Centre for Quantum Computation and Communication Technology, Griffith University, Yuggera Country, Brisbane, QLD, 4111, Australia
| | | | - Kiarn T Laverick
- Centre for Quantum Dynamics, Griffith University, Yugambeh Country, Gold Coast, QLD, 4222, Australia
| | - Ian R Berkman
- Centre for Quantum Computation and Communication Technology, School of Physics, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Sven Rogge
- Centre for Quantum Computation and Communication Technology, School of Physics, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Lynden K Shalm
- National Institute of Standards and Technology, 325 Broadway, Boulder, CO, 80305, USA
| | - Nora Tischler
- Centre for Quantum Dynamics and Centre for Quantum Computation and Communication Technology, Griffith University, Yuggera Country, Brisbane, QLD, 4111, Australia.
| | - Eric G Cavalcanti
- Centre for Quantum Dynamics, Griffith University, Yugambeh Country, Gold Coast, QLD, 4222, Australia.
| | - Sergei Slussarenko
- Centre for Quantum Dynamics and Centre for Quantum Computation and Communication Technology, Griffith University, Yuggera Country, Brisbane, QLD, 4111, Australia
| | - Geoff J Pryde
- Centre for Quantum Dynamics and Centre for Quantum Computation and Communication Technology, Griffith University, Yuggera Country, Brisbane, QLD, 4111, Australia
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5
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Huai S, Bu K, Gu X, Zhang Z, An S, Yang X, Li Y, Cai T, Zheng Y. Fast joint parity measurement via collective interactions induced by stimulated emission. Nat Commun 2024; 15:3045. [PMID: 38589424 PMCID: PMC11001884 DOI: 10.1038/s41467-024-47379-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 03/29/2024] [Indexed: 04/10/2024] Open
Abstract
Parity detection is essential in quantum error correction. Error syndromes coded in parity are detected routinely by sequential CNOT gates. Here, different from the standard CNOT-gate based scheme, we propose a reliable joint parity measurement (JPM) scheme inspired by stimulated emission. By controlling the collective behavior between data qubits and syndrome qubit, we realize the parity detection and experimentally implement the weight-2 and weight-4 JPM scheme in a tunable coupling superconducting circuit, which shows comparable performance to the CNOT scheme. Moreover, with the aid of the coupling tunability in quantum system, this scheme can be further utilized for specific joint entangling state preparation (JEP) with high fidelity, such as multiqubit entangled state preparation for non-adjacent qubits. This strategy, combined with the superconducting qubit system with tunable couplers, reveals tremendous potential and applications in the surface code architecture without adding extra circuit elements. Besides, the method we develop here can readily be applied in large-scale quantum computation and quantum simulation.
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Affiliation(s)
- Sainan Huai
- Quantum Laboratory, Tencent, 518057, Shenzhen, Guangdong, China
| | - Kunliang Bu
- Quantum Laboratory, Tencent, 518057, Shenzhen, Guangdong, China
| | - Xiu Gu
- Quantum Laboratory, Tencent, 518057, Shenzhen, Guangdong, China.
| | - Zhenxing Zhang
- Quantum Laboratory, Tencent, 518057, Shenzhen, Guangdong, China
| | - Shuoming An
- Quantum Laboratory, Tencent, 518057, Shenzhen, Guangdong, China
| | - Xiaopei Yang
- Quantum Laboratory, Tencent, 518057, Shenzhen, Guangdong, China
| | - Yuan Li
- Quantum Laboratory, Tencent, 518057, Shenzhen, Guangdong, China
| | - Tianqi Cai
- Quantum Laboratory, Tencent, 518057, Shenzhen, Guangdong, China.
| | - Yicong Zheng
- Quantum Laboratory, Tencent, 518057, Shenzhen, Guangdong, China
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6
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Mori Y, Kawabata S, Matsuzaki Y. How to experimentally evaluate the adiabatic condition for quantum annealing. Sci Rep 2024; 14:8177. [PMID: 38589470 PMCID: PMC11001971 DOI: 10.1038/s41598-024-58286-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 03/27/2024] [Indexed: 04/10/2024] Open
Abstract
We propose an experimental method for evaluating the adiabatic condition during quantum annealing (QA), which will be essential for solving practical problems. The adiabatic condition consists of the transition matrix element and the energy gap, and our method simultaneously provides information about these components without diagonalizing the Hamiltonian. The key idea is to measure the power spectrum of a time domain signal by adding an oscillating field during QA, and we can estimate the values of the transition matrix element and energy gap from the measurement output. Our results provides a powerful experimental basis for analyzing the performance of QA.
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Affiliation(s)
- Yuichiro Mori
- Global Research and Development Center for Business by Quantum-AI Technology (G-QuAT), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1, Umezono, Tsukuba, Ibaraki, 305-8568, Japan.
| | - Shiro Kawabata
- Global Research and Development Center for Business by Quantum-AI Technology (G-QuAT), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1, Umezono, Tsukuba, Ibaraki, 305-8568, Japan.
- NEC-AIST Quantum Technology Cooperative Research Laboratory, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8568, Japan.
| | - Yuichiro Matsuzaki
- Global Research and Development Center for Business by Quantum-AI Technology (G-QuAT), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1, Umezono, Tsukuba, Ibaraki, 305-8568, Japan.
- NEC-AIST Quantum Technology Cooperative Research Laboratory, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8568, Japan.
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7
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Yang TY, Wang XB. Speeding up the classical simulation of Gaussian boson sampling with limited connectivity. Sci Rep 2024; 14:7680. [PMID: 38561440 PMCID: PMC10984997 DOI: 10.1038/s41598-024-58136-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 03/26/2024] [Indexed: 04/04/2024] Open
Abstract
Gaussian boson sampling (GBS) plays a crucially important role in demonstrating quantum advantage. As a major imperfection, the limited connectivity of the linear optical network weakens the quantum advantage result in recent experiments. In this work, we introduce an enhanced classical algorithm for simulating GBS processes with limited connectivity. It computes the loop Hafnian of an n × n symmetric matrix with bandwidth w in O ( n w 2 w ) time. It is better than the previous fastest algorithm which runs in O ( n w 2 2 w ) time. This classical algorithm is helpful on clarifying how limited connectivity affects the computational complexity of GBS and tightening the boundary for achieving quantum advantage in the GBS problem.
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Affiliation(s)
- Tian-Yu Yang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, China
| | - Xiang-Bin Wang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, China.
- Jinan Institute of Quantum Technology, SAICT, Jinan, 250101, China.
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, 201315, China.
- International Quantum Academy, Shenzhen, 518048, China.
- Frontier Science Center for Quantum Information, Beijing, 100084, China.
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8
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Shaw AL, Chen Z, Choi J, Mark DK, Scholl P, Finkelstein R, Elben A, Choi S, Endres M. Benchmarking highly entangled states on a 60-atom analogue quantum simulator. Nature 2024; 628:71-77. [PMID: 38509372 PMCID: PMC10990925 DOI: 10.1038/s41586-024-07173-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 02/07/2024] [Indexed: 03/22/2024]
Abstract
Quantum systems have entered a competitive regime in which classical computers must make approximations to represent highly entangled quantum states1,2. However, in this beyond-classically-exact regime, fidelity comparisons between quantum and classical systems have so far been limited to digital quantum devices2-5, and it remains unsolved how to estimate the actual entanglement content of experiments6. Here, we perform fidelity benchmarking and mixed-state entanglement estimation with a 60-atom analogue Rydberg quantum simulator, reaching a high-entanglement entropy regime in which exact classical simulation becomes impractical. Our benchmarking protocol involves extrapolation from comparisons against an approximate classical algorithm, introduced here, with varying entanglement limits. We then develop and demonstrate an estimator of the experimental mixed-state entanglement6, finding our experiment is competitive with state-of-the-art digital quantum devices performing random circuit evolution2-5. Finally, we compare the experimental fidelity against that achieved by various approximate classical algorithms, and find that only the algorithm we introduce is able to keep pace with the experiment on the classical hardware we use. Our results enable a new model for evaluating the ability of both analogue and digital quantum devices to generate entanglement in the beyond-classically-exact regime, and highlight the evolving divide between quantum and classical systems.
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Affiliation(s)
- Adam L Shaw
- California Institute of Technology, Pasadena, CA, USA.
| | - Zhuo Chen
- Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
- The NSF AI Institute for Artificial Intelligence and Fundamental Interactions, Cambridge, MA, USA
| | - Joonhee Choi
- California Institute of Technology, Pasadena, CA, USA
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Daniel K Mark
- Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Pascal Scholl
- California Institute of Technology, Pasadena, CA, USA
| | | | - Andreas Elben
- California Institute of Technology, Pasadena, CA, USA
| | - Soonwon Choi
- Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Manuel Endres
- California Institute of Technology, Pasadena, CA, USA.
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9
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Alcazar J, Ghazi Vakili M, Kalayci CB, Perdomo-Ortiz A. Enhancing combinatorial optimization with classical and quantum generative models. Nat Commun 2024; 15:2761. [PMID: 38553469 PMCID: PMC10980691 DOI: 10.1038/s41467-024-46959-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 03/15/2024] [Indexed: 04/02/2024] Open
Abstract
Devising an efficient exploration of the search space is one of the key challenges in the design of combinatorial optimization algorithms. Here, we introduce the Generator-Enhanced Optimization (GEO) strategy: a framework that leverages any generative model (classical, quantum, or quantum-inspired) to solve optimization problems. We focus on a quantum-inspired version of GEO relying on tensor-network Born machines, and referred to hereafter as TN-GEO. To illustrate our results, we run these benchmarks in the context of the canonical cardinality-constrained portfolio optimization problem by constructing instances from the S&P 500 and several other financial stock indexes, and demonstrate how the generalization capabilities of these quantum-inspired generative models can provide real value in the context of an industrial application. We also comprehensively compare state-of-the-art algorithms and show that TN-GEO is among the best; a remarkable outcome given the solvers used in the comparison have been fine-tuned for decades in this real-world industrial application. Also, a promising step toward a practical advantage with quantum-inspired models and, subsequently, with quantum generative models.
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Affiliation(s)
- Javier Alcazar
- Zapata Computing Canada Inc., 25 Adelaide St E, Suite 1500, Toronto, ON, M5C 3A1, Canada
- Acadian Asset Management LLC, 24 King William St, London, EC4R 9AT, England
| | - Mohammad Ghazi Vakili
- Zapata Computing Canada Inc., 25 Adelaide St E, Suite 1500, Toronto, ON, M5C 3A1, Canada
- Department of Chemistry, University of Toronto, Toronto, ON, M5G 1Z8, Canada
- Department of Computer Science, University of Toronto, Toronto, ON, M5S 2E4, Canada
| | - Can B Kalayci
- Zapata Computing Canada Inc., 25 Adelaide St E, Suite 1500, Toronto, ON, M5C 3A1, Canada
- Department of Industrial Engineering, Pamukkale University, Kinikli Campus, 20160, Denizli, Turkey
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10
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Huang J, Li X, Chen X, Zhai C, Zheng Y, Chi Y, Li Y, He Q, Gong Q, Wang J. Demonstration of hypergraph-state quantum information processing. Nat Commun 2024; 15:2601. [PMID: 38521765 PMCID: PMC10960808 DOI: 10.1038/s41467-024-46830-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 03/12/2024] [Indexed: 03/25/2024] Open
Abstract
Complex entangled states are the key resources for measurement-based quantum computations, which is realised by performing a sequence of measurements on initially entangled qubits. Executable quantum algorithms in the graph-state quantum computing model are determined by the entanglement structure and the connectivity of entangled qubits. By generalisation from graph-type entanglement in which only the nearest qubits interact to a new type of hypergraph entanglement in which any subset of qubits can be arbitrarily entangled via hyperedges, hypergraph states represent more general resource states that allow arbitrary quantum computation with Pauli universality. Here we report experimental preparation, certification and processing of complete categories of four-qubit hypergraph states under the principle of local unitary equivalence, on a fully reprogrammable silicon-photonic quantum chip. Genuine multipartite entanglement for hypergraph states is certificated by the characterisation of entanglement witness, and the observation of violations of Mermin inequalities without any closure of distance or detection loopholes. A basic measurement-based protocol and an efficient resource state verification by color-encoding stabilizers are implemented with local Pauli measurement to benchmark the building blocks for hypergraph-state quantum computation. Our work prototypes hypergraph entanglement as a general resource for quantum information processing.
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Affiliation(s)
- Jieshan Huang
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China
| | - Xudong Li
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Xiaojiong Chen
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China
| | - Chonghao Zhai
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China
| | - Yun Zheng
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China
| | - Yulin Chi
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China
| | - Yan Li
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China
- Frontiers Science Center for Nano-optoelectronics and Collaborative Innovation Center of Quantum Matter, Peking University, 100871, Beijing, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, Shanxi, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, 226010, Jiangsu, China
- Hefei National Laboratory, Hefei, 230088, China
| | - Qiongyi He
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China
- Frontiers Science Center for Nano-optoelectronics and Collaborative Innovation Center of Quantum Matter, Peking University, 100871, Beijing, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, Shanxi, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, 226010, Jiangsu, China
- Hefei National Laboratory, Hefei, 230088, China
| | - Qihuang Gong
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China
- Frontiers Science Center for Nano-optoelectronics and Collaborative Innovation Center of Quantum Matter, Peking University, 100871, Beijing, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, Shanxi, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, 226010, Jiangsu, China
- Hefei National Laboratory, Hefei, 230088, China
| | - Jianwei Wang
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China.
- Frontiers Science Center for Nano-optoelectronics and Collaborative Innovation Center of Quantum Matter, Peking University, 100871, Beijing, China.
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, Shanxi, China.
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, 226010, Jiangsu, China.
- Hefei National Laboratory, Hefei, 230088, China.
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11
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Mirza AR, Chaudhry AZ. Improving the estimation of environment parameters via a two-qubit scheme. Sci Rep 2024; 14:6803. [PMID: 38514676 PMCID: PMC10958054 DOI: 10.1038/s41598-024-57150-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 03/13/2024] [Indexed: 03/23/2024] Open
Abstract
We demonstrate how using two qubits can drastically improve the estimation of environment parameters compared to using only a single qubit. The two qubits are coupled to a common harmonic oscillator environment, and the properties of the environment are imprinted upon the dynamics of the two qubits. The reduced density matrix of only one of these qubits contains a decoherence factor and an additional factor taking into account the indirect interaction induced between the qubits due to the interaction with their common environment. This additional factor can drastically improve the estimation of the environment parameters, as quantified by the quantum Fisher information. In particular, we investigate the estimation of the cutoff frequency, the coupling strength, and the temperature using our two-qubit scheme compared to simply using a single qubit. We find that the precision of the estimates can be improved by orders of magnitude.
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Affiliation(s)
- Ali Raza Mirza
- School of Science and Engineering, Lahore University of Management Sciences (LUMS), Opposite Sector U, D.H.A, Lahore, 54792, Pakistan
- Department of Physics, University of Surrey, Guildford, GU2 7XH, United Kingdom
| | - Adam Zaman Chaudhry
- School of Science and Engineering, Lahore University of Management Sciences (LUMS), Opposite Sector U, D.H.A, Lahore, 54792, Pakistan.
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12
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Eriksson AM, Sépulcre T, Kervinen M, Hillmann T, Kudra M, Dupouy S, Lu Y, Khanahmadi M, Yang J, Castillo-Moreno C, Delsing P, Gasparinetti S. Universal control of a bosonic mode via drive-activated native cubic interactions. Nat Commun 2024; 15:2512. [PMID: 38509084 PMCID: PMC10954688 DOI: 10.1038/s41467-024-46507-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 02/29/2024] [Indexed: 03/22/2024] Open
Abstract
Linear bosonic modes offer a hardware-efficient alternative for quantum information processing but require access to some nonlinearity for universal control. The lack of nonlinearity in photonics has led to encoded measurement-based quantum computing, which relies on linear operations but requires access to resourceful ('nonlinear') quantum states, such as cubic phase states. In contrast, superconducting microwave circuits offer engineerable nonlinearities but suffer from static Kerr nonlinearity. Here, we demonstrate universal control of a bosonic mode composed of a superconducting nonlinear asymmetric inductive element (SNAIL) resonator, enabled by native nonlinearities in the SNAIL element. We suppress static nonlinearities by operating the SNAIL in the vicinity of its Kerr-free point and dynamically activate nonlinearities up to third order by fast flux pulses. We experimentally realize a universal set of generalized squeezing operations, as well as the cubic phase gate, and exploit them to deterministically prepare a cubic phase state in 60 ns. Our results initiate the experimental field of polynomial quantum computing, in the continuous-variables notion originally introduced by Lloyd and Braunstein.
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Affiliation(s)
- Axel M Eriksson
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden.
| | - Théo Sépulcre
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Mikael Kervinen
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Timo Hillmann
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Marina Kudra
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Simon Dupouy
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Yong Lu
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
- Physikalisches Institut, University of Stuttgart, 70569, Stuttgart, Germany
| | - Maryam Khanahmadi
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Jiaying Yang
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Claudia Castillo-Moreno
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Per Delsing
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Simone Gasparinetti
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden.
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13
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Kuwahara T, Vu TV, Saito K. Effective light cone and digital quantum simulation of interacting bosons. Nat Commun 2024; 15:2520. [PMID: 38514614 PMCID: PMC10957968 DOI: 10.1038/s41467-024-46501-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Accepted: 02/29/2024] [Indexed: 03/23/2024] Open
Abstract
The speed limit of information propagation is one of the most fundamental features in non-equilibrium physics. The region of information propagation by finite-time dynamics is approximately restricted inside the effective light cone that is formulated by the Lieb-Robinson bound. To date, extensive studies have been conducted to identify the shape of effective light cones in most experimentally relevant many-body systems. However, the Lieb-Robinson bound in the interacting boson systems, one of the most ubiquitous quantum systems in nature, has remained a critical open problem for a long time. This study reveals a tight effective light cone to limit the information propagation in interacting bosons, where the shape of the effective light cone depends on the spatial dimension. To achieve it, we prove that the speed for bosons to clump together is finite, which in turn leads to the error guarantee of the boson number truncation at each site. Furthermore, we applied the method to provide a provably efficient algorithm for simulating the interacting boson systems. The results of this study settle the notoriously challenging problem and provide the foundation for elucidating the complexity of many-body boson systems.
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Affiliation(s)
- Tomotaka Kuwahara
- Analytical quantum complexity RIKEN Hakubi Research Team, RIKEN Center for Quantum Computing (RQC), Wako, Saitama, 351-0198, Japan.
- RIKEN Cluster for Pioneering Research (CPR), Wako, Saitama, 351-0198, Japan.
- PRESTO, Japan Science and Technology (JST), Kawaguchi, Saitama, 332-0012, Japan.
| | - Tan Van Vu
- Analytical quantum complexity RIKEN Hakubi Research Team, RIKEN Center for Quantum Computing (RQC), Wako, Saitama, 351-0198, Japan
| | - Keiji Saito
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
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14
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Klimov PV, Bengtsson A, Quintana C, Bourassa A, Hong S, Dunsworth A, Satzinger KJ, Livingston WP, Sivak V, Niu MY, Andersen TI, Zhang Y, Chik D, Chen Z, Neill C, Erickson C, Grajales Dau A, Megrant A, Roushan P, Korotkov AN, Kelly J, Smelyanskiy V, Chen Y, Neven H. Optimizing quantum gates towards the scale of logical qubits. Nat Commun 2024; 15:2442. [PMID: 38499541 PMCID: PMC10948820 DOI: 10.1038/s41467-024-46623-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 03/04/2024] [Indexed: 03/20/2024] Open
Abstract
A foundational assumption of quantum error correction theory is that quantum gates can be scaled to large processors without exceeding the error-threshold for fault tolerance. Two major challenges that could become fundamental roadblocks are manufacturing high-performance quantum hardware and engineering a control system that can reach its performance limits. The control challenge of scaling quantum gates from small to large processors without degrading performance often maps to non-convex, high-constraint, and time-dynamic control optimization over an exponentially expanding configuration space. Here we report on a control optimization strategy that can scalably overcome the complexity of such problems. We demonstrate it by choreographing the frequency trajectories of 68 frequency-tunable superconducting qubits to execute single- and two-qubit gates while mitigating computational errors. When combined with a comprehensive model of physical errors across our processor, the strategy suppresses physical error rates by ~3.7× compared with the case of no optimization. Furthermore, it is projected to achieve a similar performance advantage on a distance-23 surface code logical qubit with 1057 physical qubits. Our control optimization strategy solves a generic scaling challenge in a way that can be adapted to a variety of quantum operations, algorithms, and computing architectures.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Alexander N Korotkov
- Google AI, Mountain View, CA, USA
- Department of Electrical and Computer Engineering, University of California, Riverside, CA, USA
| | | | | | - Yu Chen
- Google AI, Mountain View, CA, USA
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15
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Xue R, Beer M, Seidler I, Humpohl S, Tu JS, Trellenkamp S, Struck T, Bluhm H, Schreiber LR. Si/SiGe QuBus for single electron information-processing devices with memory and micron-scale connectivity function. Nat Commun 2024; 15:2296. [PMID: 38485971 PMCID: PMC10940717 DOI: 10.1038/s41467-024-46519-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 02/26/2024] [Indexed: 03/18/2024] Open
Abstract
The connectivity within single carrier information-processing devices requires transport and storage of single charge quanta. Single electrons have been adiabatically transported while confined to a moving quantum dot in short, all-electrical Si/SiGe shuttle device, called quantum bus (QuBus). Here we show a QuBus spanning a length of 10 μm and operated by only six simply-tunable voltage pulses. We introduce a characterization method, called shuttle-tomography, to benchmark the potential imperfections and local shuttle-fidelity of the QuBus. The fidelity of the single-electron shuttle across the full device and back (a total distance of 19 μm) is (99.7 ± 0.3) %. Using the QuBus, we position and detect up to 34 electrons and initialize a register of 34 quantum dots with arbitrarily chosen patterns of zero and single-electrons. The simple operation signals, compatibility with industry fabrication and low spin-environment-interaction in 28Si/SiGe, promises long-range spin-conserving transport of spin qubits for quantum connectivity in quantum computing architectures.
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Affiliation(s)
- Ran Xue
- JARA-FIT Institute for Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany
| | - Max Beer
- JARA-FIT Institute for Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany
| | - Inga Seidler
- JARA-FIT Institute for Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany
| | - Simon Humpohl
- JARA-FIT Institute for Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany
- ARQUE Systems GmbH, Aachen, Germany
| | - Jhih-Sian Tu
- Helmholtz Nano Facility (HNF), Forschungszentrum Jülich, Jülich, Germany
| | - Stefan Trellenkamp
- Helmholtz Nano Facility (HNF), Forschungszentrum Jülich, Jülich, Germany
| | - Tom Struck
- JARA-FIT Institute for Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany
- ARQUE Systems GmbH, Aachen, Germany
| | - Hendrik Bluhm
- JARA-FIT Institute for Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany
- ARQUE Systems GmbH, Aachen, Germany
| | - Lars R Schreiber
- JARA-FIT Institute for Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany.
- ARQUE Systems GmbH, Aachen, Germany.
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16
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Gil-Fuster E, Eisert J, Bravo-Prieto C. Understanding quantum machine learning also requires rethinking generalization. Nat Commun 2024; 15:2277. [PMID: 38480684 PMCID: PMC10938005 DOI: 10.1038/s41467-024-45882-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 02/06/2024] [Indexed: 03/17/2024] Open
Abstract
Quantum machine learning models have shown successful generalization performance even when trained with few data. In this work, through systematic randomization experiments, we show that traditional approaches to understanding generalization fail to explain the behavior of such quantum models. Our experiments reveal that state-of-the-art quantum neural networks accurately fit random states and random labeling of training data. This ability to memorize random data defies current notions of small generalization error, problematizing approaches that build on complexity measures such as the VC dimension, the Rademacher complexity, and all their uniform relatives. We complement our empirical results with a theoretical construction showing that quantum neural networks can fit arbitrary labels to quantum states, hinting at their memorization ability. Our results do not preclude the possibility of good generalization with few training data but rather rule out any possible guarantees based only on the properties of the model family. These findings expose a fundamental challenge in the conventional understanding of generalization in quantum machine learning and highlight the need for a paradigm shift in the study of quantum models for machine learning tasks.
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Affiliation(s)
- Elies Gil-Fuster
- Dahlem Center for Complex Quantum Systems, Freie Universität Berlin, Berlin, Germany
- Fraunhofer Heinrich Hertz Institute, Berlin, Germany
| | - Jens Eisert
- Dahlem Center for Complex Quantum Systems, Freie Universität Berlin, Berlin, Germany.
- Fraunhofer Heinrich Hertz Institute, Berlin, Germany.
- Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany.
| | - Carlos Bravo-Prieto
- Dahlem Center for Complex Quantum Systems, Freie Universität Berlin, Berlin, Germany.
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17
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Fauseweh B. Quantum many-body simulations on digital quantum computers: State-of-the-art and future challenges. Nat Commun 2024; 15:2123. [PMID: 38459040 PMCID: PMC10923891 DOI: 10.1038/s41467-024-46402-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 02/14/2024] [Indexed: 03/10/2024] Open
Abstract
Simulating quantum many-body systems is a key application for emerging quantum processors. While analog quantum simulation has already demonstrated quantum advantage, its digital counterpart has recently become the focus of intense research interest due to the availability of devices that aim to realize general-purpose quantum computers. In this perspective, we give a selective overview of the currently pursued approaches, review the advances in digital quantum simulation by comparing non-variational with variational approaches and identify hardware and algorithmic challenges. Based on this review, the question arises: What are the most promising problems that can be tackled with digital quantum simulation? We argue that problems of a qualitative nature are much more suitable for near-term devices then approaches aiming purely for a quantitative accuracy improvement.
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Affiliation(s)
- Benedikt Fauseweh
- Institute for Software Technology, German Aerospace Center (DLR), Linder Höhe, 51147, Cologne, Germany.
- Department of Physics, TU Dortmund University, Otto-Hahn-Str. 4, 44227, Dortmund, Germany.
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18
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van de Stolpe GL, Kwiatkowski DP, Bradley CE, Randall J, Abobeih MH, Breitweiser SA, Bassett LC, Markham M, Twitchen DJ, Taminiau TH. Mapping a 50-spin-qubit network through correlated sensing. Nat Commun 2024; 15:2006. [PMID: 38443361 PMCID: PMC10914733 DOI: 10.1038/s41467-024-46075-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Accepted: 02/09/2024] [Indexed: 03/07/2024] Open
Abstract
Spins associated to optically accessible solid-state defects have emerged as a versatile platform for exploring quantum simulation, quantum sensing and quantum communication. Pioneering experiments have shown the sensing, imaging, and control of multiple nuclear spins surrounding a single electron spin defect. However, the accessible size of these spin networks has been constrained by the spectral resolution of current methods. Here, we map a network of 50 coupled spins through high-resolution correlated sensing schemes, using a single nitrogen-vacancy center in diamond. We develop concatenated double-resonance sequences that identify spin-chains through the network. These chains reveal the characteristic spin frequencies and their interconnections with high spectral resolution, and can be fused together to map out the network. Our results provide new opportunities for quantum simulations by increasing the number of available spin qubits. Additionally, our methods might find applications in nano-scale imaging of complex spin systems external to the host crystal.
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Affiliation(s)
- G L van de Stolpe
- QuTech, Delft University of Technology, PO Box 5046, 2600, GA Delft, The Netherlands
- Kavli Institute of Nanoscience Delft, Delft University of Technology, PO Box 5046, 2600, GA Delft, The Netherlands
| | - D P Kwiatkowski
- QuTech, Delft University of Technology, PO Box 5046, 2600, GA Delft, The Netherlands
- Kavli Institute of Nanoscience Delft, Delft University of Technology, PO Box 5046, 2600, GA Delft, The Netherlands
| | - C E Bradley
- QuTech, Delft University of Technology, PO Box 5046, 2600, GA Delft, The Netherlands
- Kavli Institute of Nanoscience Delft, Delft University of Technology, PO Box 5046, 2600, GA Delft, The Netherlands
| | - J Randall
- QuTech, Delft University of Technology, PO Box 5046, 2600, GA Delft, The Netherlands
- Kavli Institute of Nanoscience Delft, Delft University of Technology, PO Box 5046, 2600, GA Delft, The Netherlands
| | - M H Abobeih
- QuTech, Delft University of Technology, PO Box 5046, 2600, GA Delft, The Netherlands
- Kavli Institute of Nanoscience Delft, Delft University of Technology, PO Box 5046, 2600, GA Delft, The Netherlands
| | - S A Breitweiser
- Quantum Engineering Laboratory, Department of Electrical and Systems Engineering, University of Pennsylvania, 200 South 33rd Street, Philadelphia, PA, 19104, USA
| | - L C Bassett
- Quantum Engineering Laboratory, Department of Electrical and Systems Engineering, University of Pennsylvania, 200 South 33rd Street, Philadelphia, PA, 19104, USA
| | - M Markham
- Element Six Innovation, Fermi Avenue, Harwell Oxford, Didcot, Oxfordshire, OX11 0QR, UK
| | - D J Twitchen
- Element Six Innovation, Fermi Avenue, Harwell Oxford, Didcot, Oxfordshire, OX11 0QR, UK
| | - T H Taminiau
- QuTech, Delft University of Technology, PO Box 5046, 2600, GA Delft, The Netherlands.
- Kavli Institute of Nanoscience Delft, Delft University of Technology, PO Box 5046, 2600, GA Delft, The Netherlands.
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19
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Ramachandran A, Wilbur GR, Mathew R, Mason A, O'Neal S, Deppe DG, Hall KC. Robust parallel laser driving of quantum dots for multiplexing of quantum light sources. Sci Rep 2024; 14:5356. [PMID: 38438449 PMCID: PMC10912409 DOI: 10.1038/s41598-024-55634-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 02/23/2024] [Indexed: 03/06/2024] Open
Abstract
Deterministic sources of quantum light (i.e. single photons or pairs of entangled photons) are required for a whole host of applications in quantum technology, including quantum imaging, quantum cryptography and the long-distance transfer of quantum information in future quantum networks. Semiconductor quantum dots are ideal candidates for solid-state quantum emitters as these artificial atoms have large dipole moments and a quantum confined energy level structure, enabling the realization of single photon sources with high repetition rates and high single photon purity. Quantum dots may also be triggered using a laser pulse for on-demand operation. The naturally-occurring size variations in ensembles of quantum dots offers the potential to increase the bandwidth of quantum communication systems through wavelength-division multiplexing, but conventional laser triggering schemes based on Rabi rotations are ineffective when applied to inequivalent emitters. Here we report the demonstration of the simultaneous triggering of >10 quantum dots using adiabatic rapid passage. We show that high-fidelity quantum state inversion is possible in a system of quantum dots with a 15 meV range of optical transition energies using a single broadband, chirped laser pulse, laying the foundation for high-bandwidth, multiplexed quantum networks.
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Affiliation(s)
- Ajan Ramachandran
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - Grant R Wilbur
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - Reuble Mathew
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - Allister Mason
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - Sabine O'Neal
- The College of Optics and Photonics, University of Central Florida, Orlando, FL, 32816-2700, USA
- IMEC, Kissimmee, FL, 34744, USA
| | - Dennis G Deppe
- The College of Optics and Photonics, University of Central Florida, Orlando, FL, 32816-2700, USA
- SdPhotonics, Richardson, TX, 75081, USA
| | - Kimberley C Hall
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, B3H 4R2, Canada.
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20
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Jain S, Sägesser T, Hrmo P, Torkzaban C, Stadler M, Oswald R, Axline C, Bautista-Salvador A, Ospelkaus C, Kienzler D, Home J. Penning micro-trap for quantum computing. Nature 2024; 627:510-514. [PMID: 38480890 PMCID: PMC10954548 DOI: 10.1038/s41586-024-07111-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 01/24/2024] [Indexed: 03/18/2024]
Abstract
Trapped ions in radio-frequency traps are among the leading approaches for realizing quantum computers, because of high-fidelity quantum gates and long coherence times1-3. However, the use of radio-frequencies presents several challenges to scaling, including requiring compatibility of chips with high voltages4, managing power dissipation5 and restricting transport and placement of ions6. Here we realize a micro-fabricated Penning ion trap that removes these restrictions by replacing the radio-frequency field with a 3 T magnetic field. We demonstrate full quantum control of an ion in this setting, as well as the ability to transport the ion arbitrarily in the trapping plane above the chip. This unique feature of the Penning micro-trap approach opens up a modification of the quantum charge-coupled device architecture with improved connectivity and flexibility, facilitating the realization of large-scale trapped-ion quantum computing, quantum simulation and quantum sensing.
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Affiliation(s)
- Shreyans Jain
- Department of Physics, ETH Zürich, Zurich, Switzerland.
- Quantum Center, ETH Zürich, Zurich, Switzerland.
| | - Tobias Sägesser
- Department of Physics, ETH Zürich, Zurich, Switzerland
- Quantum Center, ETH Zürich, Zurich, Switzerland
| | - Pavel Hrmo
- Department of Physics, ETH Zürich, Zurich, Switzerland
- Quantum Center, ETH Zürich, Zurich, Switzerland
| | | | - Martin Stadler
- Department of Physics, ETH Zürich, Zurich, Switzerland
- Quantum Center, ETH Zürich, Zurich, Switzerland
| | - Robin Oswald
- Department of Physics, ETH Zürich, Zurich, Switzerland
- Quantum Center, ETH Zürich, Zurich, Switzerland
| | - Chris Axline
- Department of Physics, ETH Zürich, Zurich, Switzerland
| | - Amado Bautista-Salvador
- Institut für Quantenoptik, Leibniz Universität Hannover, Hannover, Germany
- Physikalisch-Technische Bundesanstalt, Braunschweig, Germany
| | - Christian Ospelkaus
- Institut für Quantenoptik, Leibniz Universität Hannover, Hannover, Germany
- Physikalisch-Technische Bundesanstalt, Braunschweig, Germany
| | - Daniel Kienzler
- Department of Physics, ETH Zürich, Zurich, Switzerland
- Quantum Center, ETH Zürich, Zurich, Switzerland
| | - Jonathan Home
- Department of Physics, ETH Zürich, Zurich, Switzerland
- Quantum Center, ETH Zürich, Zurich, Switzerland
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21
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Bravyi S, Cross AW, Gambetta JM, Maslov D, Rall P, Yoder TJ. High-threshold and low-overhead fault-tolerant quantum memory. Nature 2024; 627:778-782. [PMID: 38538939 PMCID: PMC10972743 DOI: 10.1038/s41586-024-07107-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 01/23/2024] [Indexed: 04/01/2024]
Abstract
The accumulation of physical errors1-3 prevents the execution of large-scale algorithms in current quantum computers. Quantum error correction4 promises a solution by encoding k logical qubits onto a larger number n of physical qubits, such that the physical errors are suppressed enough to allow running a desired computation with tolerable fidelity. Quantum error correction becomes practically realizable once the physical error rate is below a threshold value that depends on the choice of quantum code, syndrome measurement circuit and decoding algorithm5. We present an end-to-end quantum error correction protocol that implements fault-tolerant memory on the basis of a family of low-density parity-check codes6. Our approach achieves an error threshold of 0.7% for the standard circuit-based noise model, on par with the surface code7-10 that for 20 years was the leading code in terms of error threshold. The syndrome measurement cycle for a length-n code in our family requires n ancillary qubits and a depth-8 circuit with CNOT gates, qubit initializations and measurements. The required qubit connectivity is a degree-6 graph composed of two edge-disjoint planar subgraphs. In particular, we show that 12 logical qubits can be preserved for nearly 1 million syndrome cycles using 288 physical qubits in total, assuming the physical error rate of 0.1%, whereas the surface code would require nearly 3,000 physical qubits to achieve said performance. Our findings bring demonstrations of a low-overhead fault-tolerant quantum memory within the reach of near-term quantum processors.
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Affiliation(s)
- Sergey Bravyi
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, NY, USA
| | - Andrew W Cross
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, NY, USA
| | - Jay M Gambetta
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, NY, USA
| | - Dmitri Maslov
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, NY, USA.
| | - Patrick Rall
- IBM Quantum, MIT-IBM Watson AI Laboratory, Cambridge, MA, USA
| | - Theodore J Yoder
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, NY, USA
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22
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Cellini L, Macaluso A, Lombardi M. QAL-BP: an augmented Lagrangian quantum approach for bin packing. Sci Rep 2024; 14:5142. [PMID: 38429296 PMCID: PMC10907365 DOI: 10.1038/s41598-023-50540-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 12/21/2023] [Indexed: 03/03/2024] Open
Abstract
The bin packing is a well-known NP-Hard problem in the domain of artificial intelligence, posing significant challenges in finding efficient solutions. Conversely, recent advancements in quantum technologies have shown promising potential for achieving substantial computational speedup, particularly in certain problem classes, such as combinatorial optimization. In this study, we introduce QAL-BP, a novel Quadratic Unconstrained Binary Optimization (QUBO) formulation designed specifically for bin packing and suitable for quantum computation. QAL-BP utilizes the Augmented Lagrangian method to incorporate the bin packing constraints into the objective function while also facilitating an analytical estimation of heuristic, but empirically robust, penalty multipliers. This approach leads to a more versatile and generalizable model that eliminates the need for empirically calculating instance-dependent Lagrangian coefficients, a requirement commonly encountered in alternative QUBO formulations for similar problems. To assess the effectiveness of our proposed approach, we conduct experiments on a set of bin packing instances using a real Quantum Annealing device. Additionally, we compare the results with those obtained from two different classical solvers, namely simulated annealing and Gurobi. The experimental findings not only confirm the correctness of the proposed formulation, but also demonstrate the potential of quantum computation in effectively solving the bin packing problem, particularly as more reliable quantum technology becomes available.
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Affiliation(s)
- Lorenzo Cellini
- Department of Computer Science and Engineering, University of Bologna, Bologna, Italy.
| | - Antonio Macaluso
- Agents and Simulated Reality Department, German Research Center for Artificial Intelligence (DFKI), Saarbrücken, Germany
| | - Michele Lombardi
- Department of Computer Science and Engineering, University of Bologna, Bologna, Italy
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23
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Huang JY, Su RY, Lim WH, Feng M, van Straaten B, Severin B, Gilbert W, Dumoulin Stuyck N, Tanttu T, Serrano S, Cifuentes JD, Hansen I, Seedhouse AE, Vahapoglu E, Leon RCC, Abrosimov NV, Pohl HJ, Thewalt MLW, Hudson FE, Escott CC, Ares N, Bartlett SD, Morello A, Saraiva A, Laucht A, Dzurak AS, Yang CH. High-fidelity spin qubit operation and algorithmic initialization above 1 K. Nature 2024; 627:772-777. [PMID: 38538941 PMCID: PMC10972758 DOI: 10.1038/s41586-024-07160-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 02/05/2024] [Indexed: 04/01/2024]
Abstract
The encoding of qubits in semiconductor spin carriers has been recognized as a promising approach to a commercial quantum computer that can be lithographically produced and integrated at scale1-10. However, the operation of the large number of qubits required for advantageous quantum applications11-13 will produce a thermal load exceeding the available cooling power of cryostats at millikelvin temperatures. As the scale-up accelerates, it becomes imperative to establish fault-tolerant operation above 1 K, at which the cooling power is orders of magnitude higher14-18. Here we tune up and operate spin qubits in silicon above 1 K, with fidelities in the range required for fault-tolerant operations at these temperatures19-21. We design an algorithmic initialization protocol to prepare a pure two-qubit state even when the thermal energy is substantially above the qubit energies and incorporate radiofrequency readout to achieve fidelities up to 99.34% for both readout and initialization. We also demonstrate single-qubit Clifford gate fidelities up to 99.85% and a two-qubit gate fidelity of 98.92%. These advances overcome the fundamental limitation that the thermal energy must be well below the qubit energies for the high-fidelity operation to be possible, surmounting a main obstacle in the pathway to scalable and fault-tolerant quantum computation.
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Affiliation(s)
- Jonathan Y Huang
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales, Australia.
| | - Rocky Y Su
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales, Australia
| | - Wee Han Lim
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales, Australia
- Diraq, Sydney, New South Wales, Australia
| | - MengKe Feng
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales, Australia
| | | | - Brandon Severin
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales, Australia
- Department of Engineering Science, University of Oxford, Oxford, UK
| | - Will Gilbert
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales, Australia
- Diraq, Sydney, New South Wales, Australia
| | - Nard Dumoulin Stuyck
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales, Australia
- Diraq, Sydney, New South Wales, Australia
| | - Tuomo Tanttu
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales, Australia
- Diraq, Sydney, New South Wales, Australia
| | - Santiago Serrano
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales, Australia
| | - Jesus D Cifuentes
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales, Australia
| | - Ingvild Hansen
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales, Australia
| | - Amanda E Seedhouse
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales, Australia
| | - Ensar Vahapoglu
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales, Australia
- Diraq, Sydney, New South Wales, Australia
| | - Ross C C Leon
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales, Australia
- Quantum Motion Technologies, London, UK
| | | | | | - Michael L W Thewalt
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Fay E Hudson
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales, Australia
- Diraq, Sydney, New South Wales, Australia
| | - Christopher C Escott
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales, Australia
- Diraq, Sydney, New South Wales, Australia
| | - Natalia Ares
- Department of Engineering Science, University of Oxford, Oxford, UK
| | - Stephen D Bartlett
- Centre for Engineered Quantum Systems, School of Physics, University of Sydney, Sydney, New South Wales, Australia
| | - Andrea Morello
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales, Australia
| | - Andre Saraiva
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales, Australia
- Diraq, Sydney, New South Wales, Australia
| | - Arne Laucht
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales, Australia
- Diraq, Sydney, New South Wales, Australia
| | - Andrew S Dzurak
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales, Australia.
- Diraq, Sydney, New South Wales, Australia.
| | - Chih Hwan Yang
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales, Australia.
- Diraq, Sydney, New South Wales, Australia.
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24
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Brand D, Sinayskiy I, Petruccione F. Markovian noise modelling and parameter extraction framework for quantum devices. Sci Rep 2024; 14:4769. [PMID: 38413630 PMCID: PMC10899264 DOI: 10.1038/s41598-024-54598-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 02/14/2024] [Indexed: 02/29/2024] Open
Abstract
In recent years, Noisy Intermediate Scale Quantum (NISQ) computers have been widely used as a test bed for quantum dynamics. This work provides a new hardware-agnostic framework for modelling the Markovian noise and dynamics of quantum systems in benchmark procedures used to evaluate device performance. As an accessible example, the application and performance of this framework is demonstrated on IBM Quantum computers. This framework serves to extract multiple calibration parameters simultaneously through a simplified process which is more reliable than previously studied calibration experiments and tomographic procedures. Additionally, this method allows for real-time calibration of several hardware parameters of a quantum computer within a comprehensive procedure, providing quantitative insight into the performance of each device to be accounted for in future quantum circuits. The framework proposed here has the additional benefit of highlighting the consistency among qubit pairs when extracting parameters, which leads to a less computationally expensive calibration process than evaluating the entire device at once.
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Affiliation(s)
- Dean Brand
- Department of Physics, School of Data Science and Computational Thinking, Stellenbosch University, Stellenbosch, 7604, South Africa.
| | - Ilya Sinayskiy
- School of Chemistry and Physics, University of KwaZulu-Natal, Durban, 4001, South Africa.
- National Institute for Theoretical and Computational Sciences (NITheCS), Stellenbosch, 7604, South Africa.
| | - Francesco Petruccione
- Department of Physics, School of Data Science and Computational Thinking, Stellenbosch University, Stellenbosch, 7604, South Africa
- National Institute for Theoretical and Computational Sciences (NITheCS), Stellenbosch, 7604, South Africa
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25
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Li Z, Roy T, Rodríguez Pérez D, Lee KH, Kapit E, Schuster DI. Autonomous error correction of a single logical qubit using two transmons. Nat Commun 2024; 15:1681. [PMID: 38395989 PMCID: PMC10891116 DOI: 10.1038/s41467-024-45858-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 02/05/2024] [Indexed: 02/25/2024] Open
Abstract
Large-scale quantum computers will inevitably need quantum error correction to protect information against decoherence. Traditional error correction typically requires many qubits, along with high-efficiency error syndrome measurement and real-time feedback. Autonomous quantum error correction instead uses steady-state bath engineering to perform the correction in a hardware-efficient manner. In this work, we develop a new autonomous quantum error correction scheme that actively corrects single-photon loss and passively suppresses low-frequency dephasing, and we demonstrate an important experimental step towards its full implementation with transmons. Compared to uncorrected encoding, improvements are experimentally witnessed for the logical zero, one, and superposition states. Our results show the potential of implementing hardware-efficient autonomous quantum error correction to enhance the reliability of a transmon-based quantum information processor.
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Affiliation(s)
- Ziqian Li
- James Franck Institute, University of Chicago, Chicago, IL, 60637, USA
- Department of Physics, University of Chicago, Chicago, IL, 60637, USA
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA
| | - Tanay Roy
- James Franck Institute, University of Chicago, Chicago, IL, 60637, USA
- Department of Physics, University of Chicago, Chicago, IL, 60637, USA
| | | | - Kan-Heng Lee
- James Franck Institute, University of Chicago, Chicago, IL, 60637, USA
- Department of Physics, University of Chicago, Chicago, IL, 60637, USA
| | - Eliot Kapit
- Department of Physics, Colorado School of Mines, Golden, CO, 80401, USA
| | - David I Schuster
- James Franck Institute, University of Chicago, Chicago, IL, 60637, USA.
- Department of Physics, University of Chicago, Chicago, IL, 60637, USA.
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA.
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL, 60637, USA.
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26
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Zahidy M, Ribezzo D, De Lazzari C, Vagniluca I, Biagi N, Müller R, Occhipinti T, Oxenløwe LK, Galili M, Hayashi T, Cassioli D, Mecozzi A, Antonelli C, Zavatta A, Bacco D. Practical high-dimensional quantum key distribution protocol over deployed multicore fiber. Nat Commun 2024; 15:1651. [PMID: 38395964 PMCID: PMC10891113 DOI: 10.1038/s41467-024-45876-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 02/06/2024] [Indexed: 02/25/2024] Open
Abstract
Quantum key distribution (QKD) is a secure communication scheme for sharing symmetric cryptographic keys based on the laws of quantum physics, and is considered a key player in the realm of cyber-security. A critical challenge for QKD systems comes from the fact that the ever-increasing rates at which digital data are transmitted require more and more performing sources of quantum keys, primarily in terms of secret key generation rate. High-dimensional QKD based on path encoding has been proposed as a candidate approach to address this challenge. However, while proof-of-principle demonstrations based on lab experiments have been reported in the literature, demonstrations in realistic environments are still missing. Here we report the generation of secret keys in a 4-dimensional hybrid time-path-encoded QKD system over a 52-km deployed multicore fiber link forming by looping back two cores of a 26-km 4-core optical fiber. Our results indicate that robust high-dimensional QKD can be implemented in a realistic environment by combining standard telecom equipment with emerging multicore fiber technology.
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Affiliation(s)
- Mujtaba Zahidy
- Department of Electrical and Photonics Engineering, Technical University of Denmark, Ørsteds Pl., Kgs. Lyngby, 2800, Denmark
| | - Domenico Ribezzo
- Department of Physical and Chemical Sciences, University of L'Aquila, L'Aquila, Italy
- Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche (CNR-INO), Firenze, 50125, Italy
- University of Naples Federico II, Napoli, Italy
| | | | | | | | - Ronny Müller
- Department of Electrical and Photonics Engineering, Technical University of Denmark, Ørsteds Pl., Kgs. Lyngby, 2800, Denmark
| | | | - Leif K Oxenløwe
- Department of Electrical and Photonics Engineering, Technical University of Denmark, Ørsteds Pl., Kgs. Lyngby, 2800, Denmark
| | - Michael Galili
- Department of Electrical and Photonics Engineering, Technical University of Denmark, Ørsteds Pl., Kgs. Lyngby, 2800, Denmark
| | - Tetsuya Hayashi
- Optical Communications Laboratory, Sumitomo Electric Industries, Ltd., Yokohama, 244-8588, Japan
| | - Dajana Cassioli
- Department of Information Engineering, Computer Science and Mathematics, University of L'Aquila, L'Aquila, Italy
- National Laboratory of Advanced Optical Fibers for Photonics (FIBERS), CNIT, L'Aquila, Italy
| | - Antonio Mecozzi
- Department of Physical and Chemical Sciences, University of L'Aquila, L'Aquila, Italy
- National Laboratory of Advanced Optical Fibers for Photonics (FIBERS), CNIT, L'Aquila, Italy
| | - Cristian Antonelli
- Department of Physical and Chemical Sciences, University of L'Aquila, L'Aquila, Italy
- National Laboratory of Advanced Optical Fibers for Photonics (FIBERS), CNIT, L'Aquila, Italy
| | - Alessandro Zavatta
- Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche (CNR-INO), Firenze, 50125, Italy
- QTI S.r.l., Firenze, 50125, Italy
| | - Davide Bacco
- QTI S.r.l., Firenze, 50125, Italy.
- Department of Physics and Astronomy, University of Florence, Via Sansone 1, Firenze, 50019, Italy.
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27
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Cong I, Maskara N, Tran MC, Pichler H, Semeghini G, Yelin SF, Choi S, Lukin MD. Enhancing detection of topological order by local error correction. Nat Commun 2024; 15:1527. [PMID: 38378727 PMCID: PMC10879205 DOI: 10.1038/s41467-024-45584-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Accepted: 01/25/2024] [Indexed: 02/22/2024] Open
Abstract
The exploration of topologically-ordered states of matter is a long-standing goal at the interface of several subfields of the physical sciences. Such states feature intriguing physical properties such as long-range entanglement, emergent gauge fields and non-local correlations, and can aid in realization of scalable fault-tolerant quantum computation. However, these same features also make creation, detection, and characterization of topologically-ordered states particularly challenging. Motivated by recent experimental demonstrations, we introduce a paradigm for quantifying topological states-locally error-corrected decoration (LED)-by combining methods of error correction with ideas of renormalization-group flow. Our approach allows for efficient and robust identification of topological order, and is applicable in the presence of incoherent noise sources, making it particularly suitable for realistic experiments. We demonstrate the power of LED using numerical simulations of the toric code under a variety of perturbations. We subsequently apply it to an experimental realization, providing new insights into a quantum spin liquid created on a Rydberg-atom simulator. Finally, we extend LED to generic topological phases, including those with non-abelian order.
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Affiliation(s)
- Iris Cong
- Department of Physics, Harvard University, Cambridge, MA, 02138, USA
| | - Nishad Maskara
- Department of Physics, Harvard University, Cambridge, MA, 02138, USA
| | - Minh C Tran
- Department of Physics, Harvard University, Cambridge, MA, 02138, USA
- Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Hannes Pichler
- Institute for Theoretical Physics, University of Innsbruck, 6020, Innsbruck, Austria
- Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, 6020, Innsbruck, Austria
| | - Giulia Semeghini
- Department of Physics, Harvard University, Cambridge, MA, 02138, USA
| | - Susanne F Yelin
- Department of Physics, Harvard University, Cambridge, MA, 02138, USA
| | - Soonwon Choi
- Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Mikhail D Lukin
- Department of Physics, Harvard University, Cambridge, MA, 02138, USA.
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28
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Struck T, Volmer M, Visser L, Offermann T, Xue R, Tu JS, Trellenkamp S, Cywiński Ł, Bluhm H, Schreiber LR. Spin-EPR-pair separation by conveyor-mode single electron shuttling in Si/SiGe. Nat Commun 2024; 15:1325. [PMID: 38351007 PMCID: PMC10864332 DOI: 10.1038/s41467-024-45583-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 01/29/2024] [Indexed: 02/16/2024] Open
Abstract
Long-ranged coherent qubit coupling is a missing function block for scaling up spin qubit based quantum computing solutions. Spin-coherent conveyor-mode electron-shuttling could enable spin quantum-chips with scalable and sparse qubit-architecture. Its key feature is the operation by only few easily tuneable input terminals and compatibility with industrial gate-fabrication. Single electron shuttling in conveyor-mode in a 420 nm long quantum bus has been demonstrated previously. Here we investigate the spin coherence during conveyor-mode shuttling by separation and rejoining an Einstein-Podolsky-Rosen (EPR) spin-pair. Compared to previous work we boost the shuttle velocity by a factor of 10000. We observe a rising spin-qubit dephasing time with the longer shuttle distances due to motional narrowing and estimate the spin-shuttle infidelity due to dephasing to be 0.7% for a total shuttle distance of nominal 560 nm. Shuttling several loops up to an accumulated distance of 3.36 μm, spin-entanglement of the EPR pair is still detectable, giving good perspective for our approach of a shuttle-based scalable quantum computing architecture in silicon.
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Affiliation(s)
- Tom Struck
- JARA-FIT Institute for Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany
- ARQUE Systems GmbH, Aachen, Germany
| | - Mats Volmer
- JARA-FIT Institute for Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany
| | - Lino Visser
- JARA-FIT Institute for Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany
| | - Tobias Offermann
- JARA-FIT Institute for Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany
| | - Ran Xue
- JARA-FIT Institute for Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany
| | - Jhih-Sian Tu
- Helmholtz Nano Facility (HNF), Forschungszentrum Jülich, Jülich, Germany
| | - Stefan Trellenkamp
- Helmholtz Nano Facility (HNF), Forschungszentrum Jülich, Jülich, Germany
| | - Łukasz Cywiński
- Institute of Physics, Polish Academy of Sciences, Warsaw, Poland
| | - Hendrik Bluhm
- JARA-FIT Institute for Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany
- ARQUE Systems GmbH, Aachen, Germany
| | - Lars R Schreiber
- JARA-FIT Institute for Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany.
- ARQUE Systems GmbH, Aachen, Germany.
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29
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Chen S, Cotler J, Huang HY, Li J. Publisher Correction: The complexity of NISQ. Nat Commun 2024; 15:1308. [PMID: 38346999 PMCID: PMC10861558 DOI: 10.1038/s41467-024-45799-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2024] Open
Affiliation(s)
- Sitan Chen
- Department of Electrical Engineering and Computer Science, University of California, Berkeley, Berkeley, CA, USA.
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, USA.
| | - Jordan Cotler
- Society of Fellows, Harvard University, Cambridge, MA, USA.
| | - Hsin-Yuan Huang
- Institute for Quantum Information and Matter, CAltech, Pasadena, CA, USA.
- Department of Computing and Mathematical Sciences, CAltech, Pasadena, CA, USA.
| | - Jerry Li
- Microsoft Research AI, Redmond, WA, USA.
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30
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Ungerer JH, Pally A, Kononov A, Lehmann S, Ridderbos J, Potts PP, Thelander C, Dick KA, Maisi VF, Scarlino P, Baumgartner A, Schönenberger C. Strong coupling between a microwave photon and a singlet-triplet qubit. Nat Commun 2024; 15:1068. [PMID: 38316779 PMCID: PMC10844229 DOI: 10.1038/s41467-024-45235-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 01/18/2024] [Indexed: 02/07/2024] Open
Abstract
Combining superconducting resonators and quantum dots has triggered tremendous progress in quantum information, however, attempts at coupling a resonator to even charge parity spin qubits have resulted only in weak spin-photon coupling. Here, we integrate a zincblende InAs nanowire double quantum dot with strong spin-orbit interaction in a magnetic-field resilient, high-quality resonator. The quantum confinement in the nanowire is achieved using deterministically grown wurtzite tunnel barriers. Our experiments on even charge parity states and at large magnetic fields, allow us to identify the relevant spin states and to measure the spin decoherence rates and spin-photon coupling strengths. We find an anti-crossing between the resonator mode in the single photon limit and a singlet-triplet qubit with a spin-photon coupling strength of g/2π = 139 ± 4 MHz. This coherent coupling exceeds the resonator decay rate κ/2π = 19.8 ± 0.2 MHz and the qubit dephasing rate γ/2π = 116 ± 7 MHz, putting our system in the strong coupling regime.
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Affiliation(s)
- J H Ungerer
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland.
- Swiss Nanoscience Institute, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland.
| | - A Pally
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland.
| | - A Kononov
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland
| | - S Lehmann
- Solid State Physics and NanoLund, Lund University, Box 118, S-22100, Lund, Sweden
| | - J Ridderbos
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands
| | - P P Potts
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland
- Swiss Nanoscience Institute, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland
| | - C Thelander
- Solid State Physics and NanoLund, Lund University, Box 118, S-22100, Lund, Sweden
| | - K A Dick
- Centre for Analysis and Synthesis, Lund University, Box 124, S-22100, Lund, Sweden
| | - V F Maisi
- Solid State Physics and NanoLund, Lund University, Box 118, S-22100, Lund, Sweden
| | - P Scarlino
- Institute of Physics and Center for Quantum Science and Engineering, Ecole Polytechnique Fédérale de Lausanne, CH-1015, Lausanne, Switzerland
| | - A Baumgartner
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland
- Swiss Nanoscience Institute, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland
| | - C Schönenberger
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland
- Swiss Nanoscience Institute, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland
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31
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Sahu H, Sen K. Quantum-walk search in motion. Sci Rep 2024; 14:2815. [PMID: 38307883 PMCID: PMC10837460 DOI: 10.1038/s41598-024-51709-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 01/09/2024] [Indexed: 02/04/2024] Open
Abstract
In quantum computing, the quantum walk search algorithm is designed for locating fixed marked nodes within a graph. However, when multiple marked nodes exist, the conventional search algorithm lacks the capacity to simultaneously amplify the marked nodes as well as identify the correct chronological ordering between the marked nodes, if any. To address this limitation, we explore a potential extension of the algorithm by introducing additional quantum states to label the marked nodes. The labels resolve the ambiguity of simultaneous amplification of the marked nodes. Additionally, by associating the label states with a chronological ordering, we can extend the algorithm to track a moving particle on a two-dimensional surface. Our algorithm efficiently searches for the trajectory of the particle and is supported by a proposed quantum circuit. This concept holds promise for a range of applications, from real-time object tracking to network management and routing.
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Affiliation(s)
- Himanshu Sahu
- Department of Instrumentation and Applied Physics, Indian Institute of Sciences, C.V. Raman Avenue, Bangalore, 560012, India.
| | - Kallol Sen
- ICTP South American Institute for Fundamental Research, IFT-UNESP (1° andar), Rua Dr. Bento Teobaldo Ferraz 271, Bloco 2-Barra Funda, São Paulo, SP, 01140-070, Brazil
- Quantum Information and Computing (QuIC) Laboratory, Light and Matter Physics, Raman Research Institute, C. V. Raman Avenue Sadashivanagar, Bangalore, Karnataka, 560012, India
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32
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Bluvstein D, Evered SJ, Geim AA, Li SH, Zhou H, Manovitz T, Ebadi S, Cain M, Kalinowski M, Hangleiter D, Bonilla Ataides JP, Maskara N, Cong I, Gao X, Sales Rodriguez P, Karolyshyn T, Semeghini G, Gullans MJ, Greiner M, Vuletić V, Lukin MD. Logical quantum processor based on reconfigurable atom arrays. Nature 2024; 626:58-65. [PMID: 38056497 PMCID: PMC10830422 DOI: 10.1038/s41586-023-06927-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Accepted: 12/01/2023] [Indexed: 12/08/2023]
Abstract
Suppressing errors is the central challenge for useful quantum computing1, requiring quantum error correction (QEC)2-6 for large-scale processing. However, the overhead in the realization of error-corrected 'logical' qubits, in which information is encoded across many physical qubits for redundancy2-4, poses substantial challenges to large-scale logical quantum computing. Here we report the realization of a programmable quantum processor based on encoded logical qubits operating with up to 280 physical qubits. Using logical-level control and a zoned architecture in reconfigurable neutral-atom arrays7, our system combines high two-qubit gate fidelities8, arbitrary connectivity7,9, as well as fully programmable single-qubit rotations and mid-circuit readout10-15. Operating this logical processor with various types of encoding, we demonstrate improvement of a two-qubit logic gate by scaling surface-code6 distance from d = 3 to d = 7, preparation of colour-code qubits with break-even fidelities5, fault-tolerant creation of logical Greenberger-Horne-Zeilinger (GHZ) states and feedforward entanglement teleportation, as well as operation of 40 colour-code qubits. Finally, using 3D [[8,3,2]] code blocks16,17, we realize computationally complex sampling circuits18 with up to 48 logical qubits entangled with hypercube connectivity19 with 228 logical two-qubit gates and 48 logical CCZ gates20. We find that this logical encoding substantially improves algorithmic performance with error detection, outperforming physical-qubit fidelities at both cross-entropy benchmarking and quantum simulations of fast scrambling21,22. These results herald the advent of early error-corrected quantum computation and chart a path towards large-scale logical processors.
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Affiliation(s)
- Dolev Bluvstein
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Simon J Evered
- Department of Physics, Harvard University, Cambridge, MA, USA
| | | | - Sophie H Li
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Hengyun Zhou
- Department of Physics, Harvard University, Cambridge, MA, USA
- QuEra Computing Inc., Boston, MA, USA
| | - Tom Manovitz
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Sepehr Ebadi
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Madelyn Cain
- Department of Physics, Harvard University, Cambridge, MA, USA
| | | | - Dominik Hangleiter
- Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, MD, USA
| | | | - Nishad Maskara
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Iris Cong
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Xun Gao
- Department of Physics, Harvard University, Cambridge, MA, USA
| | | | | | - Giulia Semeghini
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Michael J Gullans
- Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, MD, USA
| | - Markus Greiner
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Vladan Vuletić
- Department of Physics and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Mikhail D Lukin
- Department of Physics, Harvard University, Cambridge, MA, USA.
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33
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Gao K, Li Y, Yang Y, Liu Y, Liu M, Liang W, Zhang B, Wang L, Zhu J, Wu K. Manipulating Coherent Exciton Dynamics in CsPbI 3 Perovskite Quantum Dots Using Magnetic Field. Adv Mater 2024; 36:e2309420. [PMID: 38009823 DOI: 10.1002/adma.202309420] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 11/02/2023] [Indexed: 11/29/2023]
Abstract
Lead halide perovskite quantum dots (QDs) have recently emerged as a promising material platform for quantum information processing owing to their strong light-matter interaction and relatively long-lived optical and spin coherences. In particular, the coherence of the fine-structure bright excitons is sustainable up to room temperature and can be observed even at an ensemble level. Here modulation of the polarization of these excitons in CsPbI3 QDs and manipulation of their time-domain coherent dynamics using a longitudinal magnetic field are demonstrated. The manipulation is realized using femtosecond quantum beat spectroscopy performed with both circularly- and linearly-polarized pulses. The results are well captured by the density of matrix simulation and are picturized using a Bloch sphere. This study forms the basis for preparing arbitrary coherent superpositions of excitons in perovskite QDs for an array of quantum technologies under near-ambient conditions.
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Affiliation(s)
- Kaimin Gao
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning, 116023, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yuxuan Li
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning, 116023, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yupeng Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning, 116023, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yuan Liu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning, 116023, China
- Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Meng Liu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning, 116023, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Wenfei Liang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning, 116023, China
| | - Boyu Zhang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning, 116023, China
| | - Lifeng Wang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning, 116023, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jingyi Zhu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning, 116023, China
| | - Kaifeng Wu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning, 116023, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
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34
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Clark G, Raniwala H, Koppa M, Chen K, Leenheer A, Zimmermann M, Dong M, Li L, Wen YH, Dominguez D, Trusheim M, Gilbert G, Eichenfield M, Englund D. Nanoelectromechanical Control of Spin-Photon Interfaces in a Hybrid Quantum System on Chip. Nano Lett 2024; 24:1316-1323. [PMID: 38227973 PMCID: PMC10835722 DOI: 10.1021/acs.nanolett.3c04301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 01/03/2024] [Accepted: 01/05/2024] [Indexed: 01/18/2024]
Abstract
Color centers (CCs) in nanostructured diamond are promising for optically linked quantum technologies. Scaling to useful applications motivates architectures meeting the following criteria: C1 individual optical addressing of spin qubits; C2 frequency tuning of spin-dependent optical transitions; C3 coherent spin control; C4 active photon routing; C5 scalable manufacturability; and C6 low on-chip power dissipation for cryogenic operations. Here, we introduce an architecture that simultaneously achieves C1-C6. We realize piezoelectric strain control of diamond waveguide-coupled tin vacancy centers with ultralow power dissipation necessary. The DC response of our device allows emitter transition tuning by over 20 GHz, combined with low-power AC control. We show acoustic spin resonance of integrated tin vacancy spins and estimate single-phonon coupling rates over 1 kHz in the resolved sideband regime. Combined with high-speed optical routing, our work opens a path to scalable single-qubit control with optically mediated entangling gates.
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Affiliation(s)
- Genevieve Clark
- The
MITRE Corporation, 202 Burlington Road, Bedford, Massachusetts 01730, United States
- Research
Laboratory of Electronics, Massachusetts
Institute of Technology, 50 Vassar Street, Cambridge, Massachusetts 02139, United States
| | - Hamza Raniwala
- Research
Laboratory of Electronics, Massachusetts
Institute of Technology, 50 Vassar Street, Cambridge, Massachusetts 02139, United States
| | - Matthew Koppa
- Sandia
National Laboratories, P.O. Box 5800, Albuquerque, New Mexico 87185, United States
| | - Kevin Chen
- Research
Laboratory of Electronics, Massachusetts
Institute of Technology, 50 Vassar Street, Cambridge, Massachusetts 02139, United States
| | - Andrew Leenheer
- Sandia
National Laboratories, P.O. Box 5800, Albuquerque, New Mexico 87185, United States
| | - Matthew Zimmermann
- The
MITRE Corporation, 202 Burlington Road, Bedford, Massachusetts 01730, United States
| | - Mark Dong
- The
MITRE Corporation, 202 Burlington Road, Bedford, Massachusetts 01730, United States
- Research
Laboratory of Electronics, Massachusetts
Institute of Technology, 50 Vassar Street, Cambridge, Massachusetts 02139, United States
| | - Linsen Li
- Research
Laboratory of Electronics, Massachusetts
Institute of Technology, 50 Vassar Street, Cambridge, Massachusetts 02139, United States
| | - Y. Henry Wen
- The
MITRE Corporation, 202 Burlington Road, Bedford, Massachusetts 01730, United States
| | - Daniel Dominguez
- Sandia
National Laboratories, P.O. Box 5800, Albuquerque, New Mexico 87185, United States
| | - Matthew Trusheim
- Research
Laboratory of Electronics, Massachusetts
Institute of Technology, 50 Vassar Street, Cambridge, Massachusetts 02139, United States
- DEVCOM,
Army Research Laboratory, Adelphi, Maryland 20783, United States
| | - Gerald Gilbert
- The
MITRE Corporation, 200
Forrestal Road, Princeton, New Jersey 08540, United States
| | - Matt Eichenfield
- College of
Optical Sciences, University of Arizona, Tucson, Arizona 85719, United States
| | - Dirk Englund
- Research
Laboratory of Electronics, Massachusetts
Institute of Technology, 50 Vassar Street, Cambridge, Massachusetts 02139, United States
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35
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Lewis L, Huang HY, Tran VT, Lehner S, Kueng R, Preskill J. Improved machine learning algorithm for predicting ground state properties. Nat Commun 2024; 15:895. [PMID: 38291046 PMCID: PMC10828424 DOI: 10.1038/s41467-024-45014-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Accepted: 01/08/2024] [Indexed: 02/01/2024] Open
Abstract
Finding the ground state of a quantum many-body system is a fundamental problem in quantum physics. In this work, we give a classical machine learning (ML) algorithm for predicting ground state properties with an inductive bias encoding geometric locality. The proposed ML model can efficiently predict ground state properties of an n-qubit gapped local Hamiltonian after learning from only [Formula: see text] data about other Hamiltonians in the same quantum phase of matter. This improves substantially upon previous results that require [Formula: see text] data for a large constant c. Furthermore, the training and prediction time of the proposed ML model scale as [Formula: see text] in the number of qubits n. Numerical experiments on physical systems with up to 45 qubits confirm the favorable scaling in predicting ground state properties using a small training dataset.
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Affiliation(s)
- Laura Lewis
- California Institute of Technology, Pasadena, CA, USA
- University of Cambridge, Cambridge, UK
| | - Hsin-Yuan Huang
- California Institute of Technology, Pasadena, CA, USA.
- Massachusetts Institute of Technology, Cambridge, MA, USA.
- Google Quantum AI, Venice, CA, USA.
| | | | | | | | - John Preskill
- California Institute of Technology, Pasadena, CA, USA
- AWS Center for Quantum Computing, Pasadena, CA, USA
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36
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Céleri LC, Rudnicki Ł. Gauge-Invariant Quantum Thermodynamics: Consequences for the First Law. Entropy (Basel) 2024; 26:111. [PMID: 38392366 PMCID: PMC10888098 DOI: 10.3390/e26020111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 01/22/2024] [Accepted: 01/23/2024] [Indexed: 02/24/2024]
Abstract
The universality of classical thermodynamics rests on the central limit theorem, due to which, measurements of thermal fluctuations are unable to reveal detailed information regarding the microscopic structure of a macroscopic body. When small systems are considered and fluctuations become important, thermodynamic quantities can be understood in the context of classical stochastic mechanics. A fundamental assumption behind thermodynamics is therefore that of coarse graining, which stems from a substantial lack of control over all degrees of freedom. However, when quantum systems are concerned, one claims a high level of control. As a consequence, information theory plays a major role in the identification of thermodynamic functions. Here, drawing from the concept of gauge symmetry-essential in all modern physical theories-we put forward a new possible intermediate route. Working within the realm of quantum thermodynamics, we explicitly construct physically motivated gauge transformations which encode a gentle variant of coarse graining behind thermodynamics. As a first application of this new framework, we reinterpret quantum work and heat, as well as the role of quantum coherence.
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Affiliation(s)
- Lucas C Céleri
- QPequi Group, Institute of Physics, Federal University of Goiás, Goiânia 74690-900, Brazil
| | - Łukasz Rudnicki
- International Centre for Theory of Quantum Technologies (ICTQT), University of Gdańsk, 80-308 Gdańsk, Poland
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37
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Date P, Smith W. Quantum discriminator for binary classification. Sci Rep 2024; 14:1328. [PMID: 38225371 PMCID: PMC10789793 DOI: 10.1038/s41598-023-46469-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 11/01/2023] [Indexed: 01/17/2024] Open
Abstract
Quantum computers have the unique ability to operate relatively quickly in high-dimensional spaces-this is sought to give them a competitive advantage over classical computers. In this work, we propose a novel quantum machine learning model called the Quantum Discriminator, which leverages the ability of quantum computers to operate in the high-dimensional spaces. The quantum discriminator is trained using a quantum-classical hybrid algorithm in [Formula: see text] time, and inferencing is performed on a universal quantum computer in [Formula: see text] time. The quantum discriminator takes as input the binary features extracted from a given datum along with a prediction qubit, and outputs the predicted label. We analyze its performance on the Iris and Bars and Stripes data sets, and show that it can attain 99% accuracy in simulation.
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Affiliation(s)
- Prasanna Date
- Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37830, USA.
| | - Wyatt Smith
- University of Tennessee, Knoxville, Tennessee, 37996, USA
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38
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Moutinho JP, Magano D, Coutinho B. On the complexity of quantum link prediction in complex networks. Sci Rep 2024; 14:1026. [PMID: 38200071 PMCID: PMC10781705 DOI: 10.1038/s41598-023-49906-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Accepted: 12/13/2023] [Indexed: 01/12/2024] Open
Abstract
Link prediction methods use patterns in known network data to infer which connections may be missing. Previous work has shown that continuous-time quantum walks can be used to represent path-based link prediction, which we further study here to develop a more optimized quantum algorithm. Using a sampling framework for link prediction, we analyze the query access to the input network required to produce a certain number of prediction samples. Considering both well-known classical path-based algorithms using powers of the adjacency matrix as well as our proposed quantum algorithm for path-based link prediction, we argue that there is a polynomial quantum advantage on the dependence on N, the number of nodes in the network. We further argue that the complexity of our algorithm, although sub-linear in N, is limited by the complexity of performing a quantum simulation of the network's adjacency matrix, which may prove to be an important problem in the development of quantum algorithms for network science in general.
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Affiliation(s)
- João P Moutinho
- Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal.
- Instituto de Telecomunicações, Lisboa, Portugal.
| | - Duarte Magano
- Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
- Instituto de Telecomunicações, Lisboa, Portugal
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39
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Liu J, Liu M, Liu JP, Ye Z, Wang Y, Alexeev Y, Eisert J, Jiang L. Towards provably efficient quantum algorithms for large-scale machine-learning models. Nat Commun 2024; 15:434. [PMID: 38199993 PMCID: PMC10781664 DOI: 10.1038/s41467-023-43957-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 11/24/2023] [Indexed: 01/12/2024] Open
Abstract
Large machine learning models are revolutionary technologies of artificial intelligence whose bottlenecks include huge computational expenses, power, and time used both in the pre-training and fine-tuning process. In this work, we show that fault-tolerant quantum computing could possibly provide provably efficient resolutions for generic (stochastic) gradient descent algorithms, scaling as [Formula: see text], where n is the size of the models and T is the number of iterations in the training, as long as the models are both sufficiently dissipative and sparse, with small learning rates. Based on earlier efficient quantum algorithms for dissipative differential equations, we find and prove that similar algorithms work for (stochastic) gradient descent, the primary algorithm for machine learning. In practice, we benchmark instances of large machine learning models from 7 million to 103 million parameters. We find that, in the context of sparse training, a quantum enhancement is possible at the early stage of learning after model pruning, motivating a sparse parameter download and re-upload scheme. Our work shows solidly that fault-tolerant quantum algorithms could potentially contribute to most state-of-the-art, large-scale machine-learning problems.
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Affiliation(s)
- Junyu Liu
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL, 60637, USA
- Department of Computer Science, The University of Chicago, Chicago, IL, 60637, USA
- Chicago Quantum Exchange, Chicago, IL, 60637, USA
- Kadanoff Center for Theoretical Physics, The University of Chicago, Chicago, IL, 60637, USA
- qBraid Co., Chicago, IL, 60615, USA
- SeQure, Chicago, IL, 60615, USA
| | - Minzhao Liu
- Department of Physics, The University of Chicago, Chicago, IL, 60637, USA
- Computational Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Jin-Peng Liu
- Simons Institute for the Theory of Computing, University of California, Berkeley, CA, 94720, USA
- Department of Mathematics, University of California, Berkeley, CA, 94720, USA
- Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Ziyu Ye
- Department of Computer Science, The University of Chicago, Chicago, IL, 60637, USA
| | - Yunfei Wang
- Martin A. Fisher School of Physics, Brandeis University, Waltham, MA, 02453, USA
| | - Yuri Alexeev
- Department of Computer Science, The University of Chicago, Chicago, IL, 60637, USA
- Chicago Quantum Exchange, Chicago, IL, 60637, USA
- Computational Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Jens Eisert
- Dahlem Center for Complex Quantum Systems, Free University Berlin, Berlin, 14195, Germany.
| | - Liang Jiang
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL, 60637, USA
- Chicago Quantum Exchange, Chicago, IL, 60637, USA
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40
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Fukami M, Marcks JC, Candido DR, Weiss LR, Soloway B, Sullivan SE, Delegan N, Heremans FJ, Flatté ME, Awschalom DD. Magnon-mediated qubit coupling determined via dissipation measurements. Proc Natl Acad Sci U S A 2024; 121:e2313754120. [PMID: 38165926 PMCID: PMC10786302 DOI: 10.1073/pnas.2313754120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 11/14/2023] [Indexed: 01/04/2024] Open
Abstract
Controlled interaction between localized and delocalized solid-state spin systems offers a compelling platform for on-chip quantum information processing with quantum spintronics. Hybrid quantum systems (HQSs) of localized nitrogen-vacancy (NV) centers in diamond and delocalized magnon modes in ferrimagnets-systems with naturally commensurate energies-have recently attracted significant attention, especially for interconnecting isolated spin qubits at length-scales far beyond those set by the dipolar coupling. However, despite extensive theoretical efforts, there is a lack of experimental characterization of the magnon-mediated interaction between NV centers, which is necessary to develop such hybrid quantum architectures. Here, we experimentally determine the magnon-mediated NV-NV coupling from the magnon-induced self-energy of NV centers. Our results are quantitatively consistent with a model in which the NV center is coupled to magnons by dipolar interactions. This work provides a versatile tool to characterize HQSs in the absence of strong coupling, informing future efforts to engineer entangled solid-state systems.
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Affiliation(s)
- Masaya Fukami
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL60637
| | - Jonathan C. Marcks
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL60637
- Center for Molecular Engineering and Materials Science Division, Argonne National Laboratory, Lemont, IL60439
| | - Denis R. Candido
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA52242
| | - Leah R. Weiss
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL60637
- Advanced Institute for Materials Research, Tohoku University, Sendai980-8577, Japan
| | - Benjamin Soloway
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL60637
| | - Sean E. Sullivan
- Center for Molecular Engineering and Materials Science Division, Argonne National Laboratory, Lemont, IL60439
| | - Nazar Delegan
- Center for Molecular Engineering and Materials Science Division, Argonne National Laboratory, Lemont, IL60439
| | - F. Joseph Heremans
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL60637
- Center for Molecular Engineering and Materials Science Division, Argonne National Laboratory, Lemont, IL60439
| | - Michael E. Flatté
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA52242
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven5600 MB, Netherlands
| | - David D. Awschalom
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL60637
- Center for Molecular Engineering and Materials Science Division, Argonne National Laboratory, Lemont, IL60439
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41
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Ahn B, Park J, Lee J, Lee S. High-dimensional single photon based quantum secure direct communication using time and phase mode degrees. Sci Rep 2024; 14:888. [PMID: 38195695 PMCID: PMC10776589 DOI: 10.1038/s41598-024-51212-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 01/02/2024] [Indexed: 01/11/2024] Open
Abstract
Quantum secure direct communication (QSDC) can guarantee security using the characteristics of quantum mechanics even when a message is directly transmitted through a quantum channel without using a secret key. However, the transmission rate of the QSDC is limited by the dead time of a single photon detector (SPD) as well as channel loss over the distance. To overcome this limited transmission rate, we propose a high-dimensional single photon-based QSDC protocol that applies two optical degrees of freedom: time and phase state. First, an N-dimensional time and phase state generation method that considers the dead time is proposed to minimize the measurement loss of a transmitted message. Second, among the two types of quantum states, the phase state with relatively low measurement efficiency is used only for eavesdropping detection, and the time state is used for sending messages with differential delay time bin-based encoding techniques. Lastly, we propose an efficient method for measuring N-dimensional time and phase-based quantum states and recovering classical bit information. This study performs security analysis against various attacks, and verifies the transmission rate improvement effect through simulation. The result indicates that our proposal can guarantee higher security and transmission rates compared to the conventional DL04 QSDC.
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Affiliation(s)
- Byungkyu Ahn
- Communication and Media Standard Lab., LG Electronics, Seoul, 06772, South Korea.
| | - Jooyoun Park
- Communication and Media Standard Lab., LG Electronics, Seoul, 06772, South Korea
| | - Jonghyun Lee
- Communication and Media Standard Lab., LG Electronics, Seoul, 06772, South Korea
| | - Sangrim Lee
- Communication and Media Standard Lab., LG Electronics, Seoul, 06772, South Korea
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42
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Gu A, Cincio L, Coles PJ. Practical Hamiltonian learning with unitary dynamics and Gibbs states. Nat Commun 2024; 15:312. [PMID: 38191523 PMCID: PMC10774402 DOI: 10.1038/s41467-023-44008-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 11/24/2023] [Indexed: 01/10/2024] Open
Abstract
We study the problem of learning the parameters for the Hamiltonian of a quantum many-body system, given limited access to the system. In this work, we build upon recent approaches to Hamiltonian learning via derivative estimation. We propose a protocol that improves the scaling dependence of prior works, particularly with respect to parameters relating to the structure of the Hamiltonian (e.g., its locality k). Furthermore, by deriving exact bounds on the performance of our protocol, we are able to provide a precise numerical prescription for theoretically optimal settings of hyperparameters in our learning protocol, such as the maximum evolution time (when learning with unitary dynamics) or minimum temperature (when learning with Gibbs states). Thanks to these improvements, our protocol has practical scaling for large problems: we demonstrate this with a numerical simulation of our protocol on an 80-qubit system.
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Affiliation(s)
- Andi Gu
- Department of Physics, University of California, Berkeley, Berkeley, CA, USA.
- Harvard Quantum Initiative, Harvard University, Cambridge, MA, 02138, USA.
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.
| | - Lukasz Cincio
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Patrick J Coles
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
- Normal Computing Corporation, New York, NY, USA
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43
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Stilck França D, Markovich LA, Dobrovitski VV, Werner AH, Borregaard J. Efficient and robust estimation of many-qubit Hamiltonians. Nat Commun 2024; 15:311. [PMID: 38191453 PMCID: PMC10774346 DOI: 10.1038/s41467-023-44012-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Accepted: 11/24/2023] [Indexed: 01/10/2024] Open
Abstract
Characterizing the interactions and dynamics of quantum mechanical systems is an essential task in developing quantum technologies. We propose an efficient protocol based on the estimation of the time-derivatives of few qubit observables using polynomial interpolation for characterizing the underlying Hamiltonian dynamics and Markovian noise of a multi-qubit device. For finite range dynamics, our protocol exponentially relaxes the necessary time-resolution of the measurements and quadratically reduces the overall sample complexity compared to previous approaches. Furthermore, we show that our protocol can characterize the dynamics of systems with algebraically decaying interactions. The implementation of the protocol requires only the preparation of product states and single-qubit measurements. Furthermore, we improve a shadow tomography method for quantum channels that is of independent interest and discuss the robustness of the protocol to various errors. This protocol can be used to parallelize the learning of the Hamiltonian, rendering it applicable for the characterization of both current and future quantum devices.
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Affiliation(s)
- Daniel Stilck França
- QMATH, Department of Mathematical Sciences, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen, Denmark.
- Univ Lyon, ENS Lyon, UCBL, CNRS, Inria, LIP, F-69342, Lyon, Cedex 07, France.
| | - Liubov A Markovich
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, 2628 CJ, The Netherlands
- Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, Leiden, 2300 RA, The Netherlands
| | - V V Dobrovitski
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, 2628 CJ, The Netherlands
| | - Albert H Werner
- QMATH, Department of Mathematical Sciences, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen, Denmark
- NBIA, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100, Copenhagen, Denmark
| | - Johannes Borregaard
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, 2628 CJ, The Netherlands
- Department of Physics, Harvard University, Cambridge, MA, 02138, USA
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44
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Feng L, Huang YY, Wu YK, Guo WX, Ma JY, Yang HX, Zhang L, Wang Y, Huang CX, Zhang C, Yao L, Qi BX, Pu YF, Zhou ZC, Duan LM. Realization of a crosstalk-avoided quantum network node using dual-type qubits of the same ion species. Nat Commun 2024; 15:204. [PMID: 38172118 PMCID: PMC10764850 DOI: 10.1038/s41467-023-44220-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Accepted: 12/05/2023] [Indexed: 01/05/2024] Open
Abstract
Generating ion-photon entanglement is a crucial step for scalable trapped-ion quantum networks. To avoid the crosstalk on memory qubits carrying quantum information, it is common to use a different ion species for ion-photon entanglement generation such that the scattered photons are far off-resonant for the memory qubits. However, such a dual-species scheme can be subject to inefficient sympathetic cooling due to the mass mismatch of the ions. Here we demonstrate a trapped-ion quantum network node in the dual-type qubit scheme where two types of qubits are encoded in the S and F hyperfine structure levels of 171Yb+ ions. We generate ion photon entanglement for the S-qubit in a typical timescale of hundreds of milliseconds, and verify its small crosstalk on a nearby F-qubit with coherence time above seconds. Our work demonstrates an enabling function of the dual-type qubit scheme for scalable quantum networks.
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Affiliation(s)
- L Feng
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, 100084, PR China
| | - Y-Y Huang
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, 100084, PR China
| | - Y-K Wu
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, 100084, PR China
- Hefei National Laboratory, Hefei, 230088, PR China
| | - W-X Guo
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, 100084, PR China
- HYQ Co. Ltd., Beijing, 100176, PR China
| | - J-Y Ma
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, 100084, PR China
- HYQ Co. Ltd., Beijing, 100176, PR China
| | - H-X Yang
- HYQ Co. Ltd., Beijing, 100176, PR China
| | - L Zhang
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, 100084, PR China
| | - Y Wang
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, 100084, PR China
| | - C-X Huang
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, 100084, PR China
| | - C Zhang
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, 100084, PR China
| | - L Yao
- HYQ Co. Ltd., Beijing, 100176, PR China
| | - B-X Qi
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, 100084, PR China
| | - Y-F Pu
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, 100084, PR China
- Hefei National Laboratory, Hefei, 230088, PR China
| | - Z-C Zhou
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, 100084, PR China
- Hefei National Laboratory, Hefei, 230088, PR China
| | - L-M Duan
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, 100084, PR China.
- Hefei National Laboratory, Hefei, 230088, PR China.
- New Cornerstone Science Laboratory, Beijing, 100084, PR China.
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45
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Gupta RS, Sundaresan N, Alexander T, Wood CJ, Merkel ST, Healy MB, Hillenbrand M, Jochym-O'Connor T, Wootton JR, Yoder TJ, Cross AW, Takita M, Brown BJ. Encoding a magic state with beyond break-even fidelity. Nature 2024; 625:259-263. [PMID: 38200302 PMCID: PMC10781628 DOI: 10.1038/s41586-023-06846-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 11/07/2023] [Indexed: 01/12/2024]
Abstract
To run large-scale algorithms on a quantum computer, error-correcting codes must be able to perform a fundamental set of operations, called logic gates, while isolating the encoded information from noise1-8. We can complete a universal set of logic gates by producing special resources called magic states9-11. It is therefore important to produce high-fidelity magic states to conduct algorithms while introducing a minimal amount of noise to the computation. Here we propose and implement a scheme to prepare a magic state on a superconducting qubit array using error correction. We find that our scheme produces better magic states than those that can be prepared using the individual qubits of the device. This demonstrates a fundamental principle of fault-tolerant quantum computing12, namely, that we can use error correction to improve the quality of logic gates with noisy qubits. Moreover, we show that the yield of magic states can be increased using adaptive circuits, in which the circuit elements are changed depending on the outcome of mid-circuit measurements. This demonstrates an essential capability needed for many error-correction subroutines. We believe that our prototype will be invaluable in the future as it can reduce the number of physical qubits needed to produce high-fidelity magic states in large-scale quantum-computing architectures.
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Affiliation(s)
- Riddhi S Gupta
- IBM Quantum, T. J. Watson Research Center, Yorktown Heights, NY, USA
- IBM Quantum, Almaden Research Center, San Jose, CA, USA
| | | | - Thomas Alexander
- IBM Quantum, T. J. Watson Research Center, Yorktown Heights, NY, USA
| | | | - Seth T Merkel
- IBM Quantum, T. J. Watson Research Center, Yorktown Heights, NY, USA
| | - Michael B Healy
- IBM Quantum, T. J. Watson Research Center, Yorktown Heights, NY, USA
| | | | - Tomas Jochym-O'Connor
- IBM Quantum, T. J. Watson Research Center, Yorktown Heights, NY, USA
- IBM Quantum, Almaden Research Center, San Jose, CA, USA
| | | | - Theodore J Yoder
- IBM Quantum, T. J. Watson Research Center, Yorktown Heights, NY, USA
| | - Andrew W Cross
- IBM Quantum, T. J. Watson Research Center, Yorktown Heights, NY, USA
| | - Maika Takita
- IBM Quantum, T. J. Watson Research Center, Yorktown Heights, NY, USA
| | - Benjamin J Brown
- IBM Quantum, T. J. Watson Research Center, Yorktown Heights, NY, USA.
- IBM Denmark, Brøndby, Denmark.
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46
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Rudolph MS, Miller J, Motlagh D, Chen J, Acharya A, Perdomo-Ortiz A. Synergistic pretraining of parametrized quantum circuits via tensor networks. Nat Commun 2023; 14:8367. [PMID: 38102108 PMCID: PMC10724286 DOI: 10.1038/s41467-023-43908-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 11/23/2023] [Indexed: 12/17/2023] Open
Abstract
Parametrized quantum circuits (PQCs) represent a promising framework for using present-day quantum hardware to solve diverse problems in materials science, quantum chemistry, and machine learning. We introduce a "synergistic" approach that addresses two prominent issues with these models: the prevalence of barren plateaus in PQC optimization landscapes, and the difficulty to outperform state-of-the-art classical algorithms. This framework first uses classical resources to compute a tensor network encoding a high-quality solution, and then converts this classical output into a PQC which can be further improved using quantum resources. We provide numerical evidence that this framework effectively mitigates barren plateaus in systems of up to 100 qubits using only moderate classical resources, with overall performance improving as more classical or quantum resources are employed. We believe our results highlight that classical simulation methods are not an obstacle to overcome in demonstrating practically useful quantum advantage, but rather can help quantum methods find their way.
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Affiliation(s)
- Manuel S Rudolph
- Zapata Computing Canada Inc., 325 Front St W, Toronto, ON, M5V 2Y1, Canada
| | - Jacob Miller
- Zapata Computing Inc., 100 Federal Street, Boston, MA, 02110, USA
| | - Danial Motlagh
- Zapata Computing Canada Inc., 325 Front St W, Toronto, ON, M5V 2Y1, Canada
| | - Jing Chen
- Zapata Computing Inc., 100 Federal Street, Boston, MA, 02110, USA
| | - Atithi Acharya
- Zapata Computing Inc., 100 Federal Street, Boston, MA, 02110, USA
- Rutgers University, 136 Frelinghuysen Rd, Piscataway, NJ, 08854, USA
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47
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Zhao H, Zhang P, Wei TC. A universal variational quantum eigensolver for non-Hermitian systems. Sci Rep 2023; 13:22313. [PMID: 38102235 PMCID: PMC10724189 DOI: 10.1038/s41598-023-49662-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 12/11/2023] [Indexed: 12/17/2023] Open
Abstract
Many quantum algorithms are developed to evaluate eigenvalues for Hermitian matrices. However, few practical approach exists for the eigenanalysis of non-Hermintian ones, such as arising from modern power systems. The main difficulty lies in the fact that, as the eigenvector matrix of a general matrix can be non-unitary, solving a general eigenvalue problem is inherently incompatible with existing unitary-gate-based quantum methods. To fill this gap, this paper introduces a Variational Quantum Universal Eigensolver (VQUE), which is deployable on noisy intermediate scale quantum computers. Our new contributions include: (1) The first universal variational quantum algorithm capable of evaluating the eigenvalues of non-Hermitian matrices-Inspired by Schur's triangularization theory, VQUE unitarizes the eigenvalue problem to a procedure of searching unitary transformation matrices via quantum devices; (2) A Quantum Process Snapshot technique is devised to make VQUE maintain the potential quantum advantage inherited from the original variational quantum eigensolver-With additional [Formula: see text] quantum gates, this method efficiently identifies whether a unitary operator is triangular with respect to a given basis; (3) Successful deployment and validation of VQUE on a real noisy quantum computer, which demonstrates the algorithm's feasibility. We also undertake a comprehensive parametric study to validate VQUE's scalability, generality, and performance in realistic applications.
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Affiliation(s)
- Huanfeng Zhao
- Department of Electrical and Computer Engineering, Stony Brook University, Stony Brook, 11794, USA
| | - Peng Zhang
- Department of Electrical and Computer Engineering, Stony Brook University, Stony Brook, 11794, USA.
| | - Tzu-Chieh Wei
- C. N. Yang Institute for Theoretical Physics, Stony Brook University, Stony Brook, 11794, USA
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48
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Qiu X, Guo H, Chen L. Remote transport of high-dimensional orbital angular momentum states and ghost images via spatial-mode-engineered frequency conversion. Nat Commun 2023; 14:8244. [PMID: 38092751 PMCID: PMC10719309 DOI: 10.1038/s41467-023-43950-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 11/24/2023] [Indexed: 12/17/2023] Open
Abstract
The efficient transport and engineering of photonic orbital angular momentum (OAM) lie at the heart of various related classical and quantum applications. Here, by leveraging the spatial-mode-engineered frequency conversion, we realize the remote transport of high-dimensional orbital angular momentum (OAM) states between two distant parties without direct transmission of information carriers. We exploit perfect vortices for preparing high-dimensional yet maximal O AM entanglement. Based on nonlinear sum-frequency generation working with a strong coherent wave packet and a single photon, we conduct the Bell-like state measurements for high-dimensional perfect vortices. We experimentally achieve an average transport fidelity 0.879 ± 0.048 and 0.796 ± 0.066 for a complete set of 3-dimensional and 5-dimensional OAM mutually unbiased bases, respectively. Furthermore, by exploring the full transverse entanglement, we construct another strategy of quantum imaging with interaction-free light. It is expected that, with the future advances in nonlinear frequency conversion, our scheme will pave the way for realizing truly secure high-dimensional quantum teleportation in the upcoming quantum network.
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Affiliation(s)
- Xiaodong Qiu
- Department of Physics, Xiamen University, Xiamen, 361005, China
| | - Haoxu Guo
- Department of Physics, Xiamen University, Xiamen, 361005, China
| | - Lixiang Chen
- Department of Physics, Xiamen University, Xiamen, 361005, China.
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49
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Stoll EA. A thermodynamical model of non-deterministic computation in cortical neural networks. Phys Biol 2023; 21:016003. [PMID: 38078366 DOI: 10.1088/1478-3975/ad0f2d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 11/23/2023] [Indexed: 12/18/2023]
Abstract
Neuronal populations in the cerebral cortex engage in probabilistic coding, effectively encoding the state of the surrounding environment with high accuracy and extraordinary energy efficiency. A new approach models the inherently probabilistic nature of cortical neuron signaling outcomes as a thermodynamic process of non-deterministic computation. A mean field approach is used, with the trial Hamiltonian maximizing available free energy and minimizing the net quantity of entropy, compared with a reference Hamiltonian. Thermodynamic quantities are always conserved during the computation; free energy must be expended to produce information, and free energy is released during information compression, as correlations are identified between the encoding system and its surrounding environment. Due to the relationship between the Gibbs free energy equation and the Nernst equation, any increase in free energy is paired with a local decrease in membrane potential. As a result, this process of thermodynamic computation adjusts the likelihood of each neuron firing an action potential. This model shows that non-deterministic signaling outcomes can be achieved by noisy cortical neurons, through an energy-efficient computational process that involves optimally redistributing a Hamiltonian over some time evolution. Calculations demonstrate that the energy efficiency of the human brain is consistent with this model of non-deterministic computation, with net entropy production far too low to retain the assumptions of a classical system.
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Affiliation(s)
- Elizabeth A Stoll
- Western Institute for Advanced Study, Denver, Colorado, United States of America
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50
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Shen YR, Chen TH, Liang SL, Cheng XY, Lv JW, Jiang YX, Cheng L, Yu YB, Jin GR, Chen AX. The generation of genuine quadripartite Einstein-Podolsky-Rosen steering in an optical superlattice. Sci Rep 2023; 13:21196. [PMID: 38040917 PMCID: PMC10692164 DOI: 10.1038/s41598-023-48626-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 11/28/2023] [Indexed: 12/03/2023] Open
Abstract
Einstein-Podolsky-Rosen (EPR) steering is a quantum effect based on quantum entanglement and it is the key resource for building quantum networks because of its useful properties. Based on the criterion for genuine multipartite EPR steering, the genuine quadripartite EPR steering is confirmed and it can be generated by a spontaneous parametric down-conversion cascaded process with two sum-frequency generations in an optical superlattice. This occurs either below the oscillation threshold and without oscillation threshold. The influence of the parameters of cascaded nonlinear process on the quadripartite EPR steering among signal, idler, and two sum-frequency beams are also discussed. Choosing appropriate nonlinear parameters can achieve good quadripartite quantum steering. This scheme of the generation of genuine quadripartite EPR steering has potential applications in quantum communication and computing.
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Affiliation(s)
- Y R Shen
- Key Laboratory of Optical Field Manipulation of Zhejiang Province, Department of Physics, Zhejiang Sci-Tech University, Hangzhou, 310018, China
| | - T H Chen
- Key Laboratory of Optical Field Manipulation of Zhejiang Province, Department of Physics, Zhejiang Sci-Tech University, Hangzhou, 310018, China
| | - S L Liang
- Key Laboratory of Optical Field Manipulation of Zhejiang Province, Department of Physics, Zhejiang Sci-Tech University, Hangzhou, 310018, China
| | - X Y Cheng
- Key Laboratory of Optical Field Manipulation of Zhejiang Province, Department of Physics, Zhejiang Sci-Tech University, Hangzhou, 310018, China
| | - J W Lv
- Key Laboratory of Optical Field Manipulation of Zhejiang Province, Department of Physics, Zhejiang Sci-Tech University, Hangzhou, 310018, China
| | - Y X Jiang
- Key Laboratory of Optical Field Manipulation of Zhejiang Province, Department of Physics, Zhejiang Sci-Tech University, Hangzhou, 310018, China
| | - L Cheng
- Key Laboratory of Optical Field Manipulation of Zhejiang Province, Department of Physics, Zhejiang Sci-Tech University, Hangzhou, 310018, China.
| | - Y B Yu
- Key Laboratory of Optical Field Manipulation of Zhejiang Province, Department of Physics, Zhejiang Sci-Tech University, Hangzhou, 310018, China.
| | - G R Jin
- Key Laboratory of Optical Field Manipulation of Zhejiang Province, Department of Physics, Zhejiang Sci-Tech University, Hangzhou, 310018, China
| | - A X Chen
- Key Laboratory of Optical Field Manipulation of Zhejiang Province, Department of Physics, Zhejiang Sci-Tech University, Hangzhou, 310018, China
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