1
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Wu HB, Liu YJ, Liu YD, Liu JJ. Resonant exchange of chiral Majorana Fermions modulated by two parallel quantum dots. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:345301. [PMID: 38729174 DOI: 10.1088/1361-648x/ad49fc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 05/10/2024] [Indexed: 05/12/2024]
Abstract
Resonant exchange of the chiral Majorana fermions (MFs) that is coupled to two parallel Majorana zero modes (MZMs) or two parallel quantum dots (QDs) is investigated. We find that, in the two QDs coupling case, the resonant exchange for the chiral MFs is analogous to that in the MZM coupling case. We further propose a circuit based on topological superconductor, which is formed by the proximity coupling of a quantum anomalous Hall insulator and a s-wave superconductor, to observe the resonant exchange of chiral MFs pairs. The numerical calculations show that the resonant transmission of the chiral MFs can be adjusted by varying the coupling parameters at superconductor phase differenceΔφ=π. It is particularly noteworthy that, by only modulating the coupling strength between the two QDs, the resonant exchange may be switched on or off. By adding another MZM, the non-Abelian braiding like operation can be realized. Therefore, our design scheme may provide another way for non-Abelian braiding operation of MFs and the findings may have potential application value in the realization of topological quantum computers.
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Affiliation(s)
- Hai-Bin Wu
- College of Science, Shijiazhuang University, Shijiazhuang 050035, People's Republic of China
| | - Yan-Jun Liu
- College of Science, Shijiazhuang University, Shijiazhuang 050035, People's Republic of China
| | - Ying-Di Liu
- College of Science, Shijiazhuang University, Shijiazhuang 050035, People's Republic of China
| | - Jian-Jun Liu
- College of Science, Shijiazhuang University, Shijiazhuang 050035, People's Republic of China
- College of Physics, Hebei Normal University, Shijiazhuang 050024, People's Republic of China
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2
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Qin H, Che L, Wei C, Xu F, Huang Y, Xin T. Experimental Direct Quantum Fidelity Learning via a Data-Driven Approach. PHYSICAL REVIEW LETTERS 2024; 132:190801. [PMID: 38804925 DOI: 10.1103/physrevlett.132.190801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 03/11/2024] [Indexed: 05/29/2024]
Abstract
Fidelity estimation is an important technique for evaluating prepared quantum states in noisy quantum devices. A recent theoretical work proposed a frugal approach called neural quantum fidelity estimation (NQFE) [X. Zhang et al., Phys. Rev. Lett. 127, 130503 (2021).PRLTAO0031-900710.1103/PhysRevLett.127.130503]. While this requires a much smaller number of measurement operators than full quantum state tomography, it uses a weight-based floating measurement strategy that predetermines the top global Pauli operators that contribute the most to the fidelity and uses discrete fidelity intervals as predictions. In this Letter, we develop a measurement-fixed NQFE based on a transformer model which requires less measurement cost and can output continuous estimates of fidelity. Here we further experimentally apply the NQFE in a realistic situation using a nuclear spin quantum processor. We prepare the ground states of local Hamiltonians and arbitrary states and investigate how to estimate their fidelity with reference states, and we compare the fidelity estimation strategy with our and the original NQFE to conventional tomography. It is shown that NQFE can estimate the fidelity with comparable accuracy to the tomography approach. In the future, NQFE will become an important tool for benchmarking quantum states ahead of the advent of well-trusted fault-tolerant quantum computers.
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Affiliation(s)
- Haiyang Qin
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China; Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China and Shenzhen Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Liangyu Che
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China; Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China and Shenzhen Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Chao Wei
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China; Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China and Shenzhen Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Feng Xu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China; Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China and Shenzhen Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yulei Huang
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China; Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China and Shenzhen Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Tao Xin
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China; Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China and Shenzhen Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
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3
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Karamlou AH, Rosen IT, Muschinske SE, Barrett CN, Di Paolo A, Ding L, Harrington PM, Hays M, Das R, Kim DK, Niedzielski BM, Schuldt M, Serniak K, Schwartz ME, Yoder JL, Gustavsson S, Yanay Y, Grover JA, Oliver WD. Probing entanglement in a 2D hard-core Bose-Hubbard lattice. Nature 2024; 629:561-566. [PMID: 38658761 PMCID: PMC11096108 DOI: 10.1038/s41586-024-07325-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 03/15/2024] [Indexed: 04/26/2024]
Abstract
Entanglement and its propagation are central to understanding many physical properties of quantum systems1-3. Notably, within closed quantum many-body systems, entanglement is believed to yield emergent thermodynamic behaviour4-7. However, a universal understanding remains challenging owing to the non-integrability and computational intractability of most large-scale quantum systems. Quantum hardware platforms provide a means to study the formation and scaling of entanglement in interacting many-body systems8-14. Here we use a controllable 4 × 4 array of superconducting qubits to emulate a 2D hard-core Bose-Hubbard (HCBH) lattice. We generate superposition states by simultaneously driving all lattice sites and extract correlation lengths and entanglement entropy across its many-body energy spectrum. We observe volume-law entanglement scaling for states at the centre of the spectrum and a crossover to the onset of area-law scaling near its edges.
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Affiliation(s)
- Amir H Karamlou
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Google Quantum AI, Santa Barbara, CA, USA.
| | - Ilan T Rosen
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Sarah E Muschinske
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Cora N Barrett
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Physics, Wellesley College, Wellesley, MA, USA
| | - Agustin Di Paolo
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Leon Ding
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Patrick M Harrington
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Max Hays
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | | | | | | | - Kyle Serniak
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
- MIT Lincoln Laboratory, Lexington, MA, USA
| | | | | | - Simon Gustavsson
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Yariv Yanay
- Laboratory for Physical Sciences, College Park, MD, USA
| | - Jeffrey A Grover
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - William D Oliver
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.
- MIT Lincoln Laboratory, Lexington, MA, USA.
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4
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Singh H, Kolodrubetz MH, Gopalakrishnan S, Vasseur R. Tunable Superdiffusion in Integrable Spin Chains Using Correlated Initial States. PHYSICAL REVIEW LETTERS 2024; 132:176303. [PMID: 38728724 DOI: 10.1103/physrevlett.132.176303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 02/05/2024] [Accepted: 04/01/2024] [Indexed: 05/12/2024]
Abstract
Although integrable spin chains host only ballistically propagating particles, they can still feature diffusive charge transfer. This diffusive charge transfer originates from quasiparticle charge fluctuations inherited from the initial state's magnetization Gaussian fluctuations. We show that ensembles of initial states with quasi-long-range correlations lead to superdiffusive charge transfer with a tunable dynamical exponent. We substantiate our prediction with numerical simulations and discuss how finite time and finite size effects might cause deviations.
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Affiliation(s)
- Hansveer Singh
- Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - Michael H Kolodrubetz
- Department of Physics, The University of Texas at Dallas, Richardson, Texas 75080, USA
| | - Sarang Gopalakrishnan
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Romain Vasseur
- Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, USA
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5
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Chen L, Wu B, Lu L, Wang K, Lu Y, Zhu S, Ma XS. Observation of quantum nonlocality in Greenberger-Horne-Zeilinger entanglement on a silicon chip. OPTICS EXPRESS 2024; 32:14904-14913. [PMID: 38859154 DOI: 10.1364/oe.515070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 03/23/2024] [Indexed: 06/12/2024]
Abstract
Nonlocality is the defining feature of quantum entanglement. Entangled states with multiple particles are of crucial importance in fundamental tests of quantum physics as well as in many quantum information tasks. One of the archetypal multipartite quantum states, Greenberger-Horne-Zeilinger (GHZ) state, allows one to observe the striking conflict of quantum physics to local realism in the so-called all-versus-nothing way. This is profoundly different from Bell's theorem for two particles, which relies on statistical predictions. Here, we demonstrate an integrated photonic chip capable of generating and manipulating the four-photon GHZ state. We perform a complete characterization of the four-photon GHZ state using quantum state tomography and obtain a state fidelity of 0.729±0.006. We further use the all-versus-nothing test and the Mermin inequalities to witness the quantum nonlocality of GHZ entanglement. Our work paves the way to perform fundamental tests of quantum physics with complex integrated quantum devices.
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6
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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] [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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7
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Zhang X, Hu Z, Liu YC. Fast Generation of GHZ-like States Using Collective-Spin XYZ Model. PHYSICAL REVIEW LETTERS 2024; 132:113402. [PMID: 38563940 DOI: 10.1103/physrevlett.132.113402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 02/14/2024] [Indexed: 04/04/2024]
Abstract
The Greenberger-Horne-Zeilinger (GHZ) state is a key resource for quantum information processing and quantum metrology. The atomic GHZ state can be generated by one-axis twisting (OAT) interaction H_{OAT}=χJ_{z}^{2} with χ the interaction strength, but it requires a long evolution time χt=π/2 and is thus seriously influenced by decoherence and losses. Here we propose a three-body collective-spin XYZ model which creates a GHZ-like state in a very short timescale χt∼lnN/N for N particles. We show that this model can be effectively produced by applying Floquet driving to an original OAT Hamiltonian. Compared with the ideal GHZ state, the GHZ-like state generated using our model can maintain similar metrological properties reaching the Heisenberg-limited scaling, and it shows better robustness to decoherence and particle losses. This Letter opens the avenue for generating GHZ-like states with a large particle number, which holds great potential for the study of macroscopic quantum effects and for applications in quantum metrology and quantum information.
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Affiliation(s)
- Xuanchen Zhang
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Zhiyao Hu
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
- School of Physics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Yong-Chun Liu
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Beijing 100084, China
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8
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Charles C, Gustafson EJ, Hardt E, Herren F, Hogan N, Lamm H, Starecheski S, Van de Water RS, Wagman ML. Simulating Z_{2} lattice gauge theory on a quantum computer. Phys Rev E 2024; 109:015307. [PMID: 38366518 DOI: 10.1103/physreve.109.015307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 12/21/2023] [Indexed: 02/18/2024]
Abstract
The utility of quantum computers for simulating lattice gauge theories is currently limited by the noisiness of the physical hardware. Various quantum error mitigation strategies exist to reduce the statistical and systematic uncertainties in quantum simulations via improved algorithms and analysis strategies. We perform quantum simulations of Z_{2} gauge theory with matter to study the efficacy and interplay of different error mitigation methods: readout error mitigation, randomized compiling, rescaling, and dynamical decoupling. We compute Minkowski correlation functions in this confining gauge theory and extract the mass of the lightest spin-1 state from fits to their time dependence. Quantum error mitigation extends the range of times over which our correlation function calculations are accurate by a factor of 6 and is therefore essential for obtaining reliable masses.
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Affiliation(s)
- Clement Charles
- Department of Physics, The University of the West Indies, St. Augustine Campus, Trinidad and Tobago
- Physics Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Erik J Gustafson
- Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA
- Quantum Artificial Intelligence Laboratory (QuAIL), NASA Ames Research Center, Moffett Field, California 94035, USA
- USRA Research Institute for Advanced Computer Science (RIACS), Mountain View, California 94043, USA
| | - Elizabeth Hardt
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, USA
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Florian Herren
- Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA
| | - Norman Hogan
- Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Henry Lamm
- Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA
| | - Sara Starecheski
- Department of Physics, Sarah Lawrence College, Bronxville, New York 10708, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | | | - Michael L Wagman
- Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA
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9
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Han PR, Wu F, Huang XJ, Wu HZ, Zou CL, Yi W, Zhang M, Li H, Xu K, Zheng D, Fan H, Wen J, Yang ZB, Zheng SB. Exceptional Entanglement Phenomena: Non-Hermiticity Meeting Nonclassicality. PHYSICAL REVIEW LETTERS 2023; 131:260201. [PMID: 38215365 DOI: 10.1103/physrevlett.131.260201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 11/15/2023] [Indexed: 01/14/2024]
Abstract
Non-Hermitian (NH) extension of quantum-mechanical Hamiltonians represents one of the most significant advancements in physics. During the past two decades, numerous captivating NH phenomena have been revealed and demonstrated, but all of which can appear in both quantum and classical systems. This leads to the fundamental question: what NH signature presents a radical departure from classical physics? The solution of this problem is indispensable for exploring genuine NH quantum mechanics, but remains experimentally untouched so far. Here, we resolve this basic issue by unveiling distinct exceptional entanglement phenomena, exemplified by an entanglement transition, occurring at the exceptional point of NH interacting quantum systems. We illustrate and demonstrate such purely quantum-mechanical NH effects with a naturally dissipative light-matter system, engineered in a circuit quantum electrodynamics architecture. Our results lay the foundation for studies of genuinely quantum-mechanical NH physics, signified by exceptional-point-enabled entanglement behaviors.
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Affiliation(s)
- Pei-Rong Han
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, Fujian 350108, China
| | - Fan Wu
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, Fujian 350108, China
| | - Xin-Jie Huang
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, Fujian 350108, China
| | - Huai-Zhi Wu
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, Fujian 350108, China
| | - Chang-Ling Zou
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China
- CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
- Hefei National Laboratory, Hefei 230088, China
| | - Wei Yi
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China
- CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
- Hefei National Laboratory, Hefei 230088, China
| | - Mengzhen Zhang
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
| | - Hekang Li
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Kai Xu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
- Hefei National Laboratory, Hefei 230088, China
| | - Dongning Zheng
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
- Hefei National Laboratory, Hefei 230088, China
| | - Heng Fan
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
- Hefei National Laboratory, Hefei 230088, China
| | - Jianming Wen
- Department of Physics, Kennesaw State University, Marietta, Georgia 30060, USA
| | - Zhen-Biao Yang
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, Fujian 350108, China
- Hefei National Laboratory, Hefei 230088, China
| | - Shi-Biao Zheng
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, Fujian 350108, China
- Hefei National Laboratory, Hefei 230088, China
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10
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Zheng RH, Ning W, Chen YH, Lü JH, Shen LT, Xu K, Zhang YR, Xu D, Li H, Xia Y, Wu F, Yang ZB, Miranowicz A, Lambert N, Zheng D, Fan H, Nori F, Zheng SB. Observation of a Superradiant Phase Transition with Emergent Cat States. PHYSICAL REVIEW LETTERS 2023; 131:113601. [PMID: 37774281 DOI: 10.1103/physrevlett.131.113601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 05/29/2023] [Accepted: 08/10/2023] [Indexed: 10/01/2023]
Abstract
Superradiant phase transitions (SPTs) are important for understanding light-matter interactions at the quantum level, and play a central role in criticality-enhanced quantum sensing. So far, SPTs have been observed in driven-dissipative systems, but the emergent light fields did not show any nonclassical characteristic due to the presence of strong dissipation. Here we report an experimental demonstration of the SPT featuring the emergence of a highly nonclassical photonic field, realized with a resonator coupled to a superconducting qubit, implementing the quantum Rabi model. We fully characterize the light-matter state by Wigner matrix tomography. The measured matrix elements exhibit quantum interference intrinsic of a photonic mesoscopic superposition, and reveal light-matter entanglement.
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Affiliation(s)
- Ri-Hua Zheng
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, Fujian 350108, China
| | - Wen Ning
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, Fujian 350108, China
| | - Ye-Hong Chen
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, Fujian 350108, China
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
- Quantum Information Physics Theory Research Team, RIKEN Center for Quantum Computing (RQC), Wako-shi, Saitama 351-0198, Japan
| | - Jia-Hao Lü
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, Fujian 350108, China
| | - Li-Tuo Shen
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, Fujian 350108, China
| | - Kai Xu
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Yu-Ran Zhang
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
- Quantum Information Physics Theory Research Team, RIKEN Center for Quantum Computing (RQC), Wako-shi, Saitama 351-0198, Japan
- School of Physics and Optoelectronics, South China University of Technology, Guangzhou 510640, China
| | - Da Xu
- Interdisciplinary Center of Quantum Information, State Key Laboratory of Modern Optical Instrumentation and Zhejiang Province Key Laboratory of Quantum Technology and Device, School of Physics, Zhejiang University, Hangzhou 310027, China
| | - Hekang Li
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Yan Xia
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, Fujian 350108, China
| | - Fan Wu
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, Fujian 350108, China
| | - Zhen-Biao Yang
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, Fujian 350108, China
| | - Adam Miranowicz
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
- Institute of Spintronics and Quantum Information, Faculty of Physics, Adam Mickiewicz University, 61-614 Poznań, Poland
| | - Neill Lambert
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
| | - Dongning Zheng
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Heng Fan
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Franco Nori
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
- Quantum Information Physics Theory Research Team, RIKEN Center for Quantum Computing (RQC), Wako-shi, Saitama 351-0198, Japan
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040, USA
| | - Shi-Biao Zheng
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, Fujian 350108, China
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11
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Lin T, Gu SS, Xu YQ, Jiang SL, Ye SK, Wang BC, Li HO, Guo GC, Zou CL, Hu X, Cao G, Guo GP. Collective Microwave Response for Multiple Gate-Defined Double Quantum Dots. NANO LETTERS 2023; 23:4176-4182. [PMID: 37133858 DOI: 10.1021/acs.nanolett.3c00036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We fabricate and characterize a hybrid quantum device that consists of five gate-defined double quantum dots (DQDs) and a high-impedance NbTiN transmission resonator. The controllable interactions between DQDs and the resonator are spectroscopically explored by measuring the microwave transmission through the resonator in the detuning parameter space. Utilizing the high tunability of the system parameters and the high cooperativity (Ctotal > 17.6) interaction between the qubit ensemble and the resonator, we tune the charge-photon coupling and observe the collective microwave response changing from linear to nonlinear. Our results present the maximum number of DQDs coupled to a resonator and manifest a potential platform for scaling up qubits and studying collective quantum effects in semiconductor-superconductor hybrid cavity quantum electrodynamics systems.
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Affiliation(s)
- Ting Lin
- Chinese Academy of Science Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- Chinese Academy of Science Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Si-Si Gu
- Chinese Academy of Science Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- Chinese Academy of Science Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yong-Qiang Xu
- Chinese Academy of Science Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- Chinese Academy of Science Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Shun-Li Jiang
- Chinese Academy of Science Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- Chinese Academy of Science Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Shu-Kun Ye
- Chinese Academy of Science Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- Chinese Academy of Science Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Bao-Chuan Wang
- Chinese Academy of Science Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- Chinese Academy of Science Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Hai-Ou Li
- Chinese Academy of Science Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- Chinese Academy of Science Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
| | - Guang-Can Guo
- Chinese Academy of Science Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- Chinese Academy of Science Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
| | - Chang-Ling Zou
- Chinese Academy of Science Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- Chinese Academy of Science Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
| | - Xuedong Hu
- Department of Physics, University at Buffalo, State University of New York, Buffalo, New York 14260-1500, United States of America
| | - Gang Cao
- Chinese Academy of Science Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- Chinese Academy of Science Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
| | - Guo-Ping Guo
- Chinese Academy of Science Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- Chinese Academy of Science Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
- Origin Quantum Computing Company Limited, Hefei, Anhui 230088, China
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12
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Liu T, Liu S, Li H, Li H, Huang K, Xiang Z, Song X, Xu K, Zheng D, Fan H. Observation of entanglement transition of pseudo-random mixed states. Nat Commun 2023; 14:1971. [PMID: 37031244 PMCID: PMC10082798 DOI: 10.1038/s41467-023-37511-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 03/17/2023] [Indexed: 04/10/2023] Open
Abstract
Random quantum states serve as a powerful tool in various scientific fields, including quantum supremacy and black hole physics. It has been theoretically predicted that entanglement transitions may happen for different partitions of multipartite random quantum states; however, the experimental observation of these transitions is still absent. Here, we experimentally demonstrate the entanglement transitions witnessed by negativity on a fully connected superconducting processor. We apply parallel entangling operations, that significantly decrease the depth of the pseudo-random circuits, to generate pseudo-random pure states of up to 15 qubits. By quantum state tomography of the reduced density matrix of six qubits, we measure the negativity spectra. Then, by changing the sizes of the environment and subsystems, we observe the entanglement transitions that are directly identified by logarithmic entanglement negativities based on the negativity spectra. In addition, we characterize the randomness of our circuits by measuring the distance between the distribution of output bit-string probabilities and the Porter-Thomas distribution. Our results show that superconducting processors with all-to-all connectivity constitute a promising platform for generating random states and understanding the entanglement structure of multipartite quantum systems.
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Affiliation(s)
- Tong Liu
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Shang Liu
- Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA, 93106, USA
| | - Hekang Li
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Hao Li
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Kaixuan Huang
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China
| | - Zhongcheng Xiang
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China
- Hefei National Laboratory, Hefei, 230088, China
- CAS Center of Excellence for Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, 100190, China
- Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China
| | - Xiaohui Song
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China
- Hefei National Laboratory, Hefei, 230088, China
- CAS Center of Excellence for Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, 100190, China
- Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China
| | - Kai Xu
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China.
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China.
- Hefei National Laboratory, Hefei, 230088, China.
- CAS Center of Excellence for Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, 100190, China.
- Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China.
| | - Dongning Zheng
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China.
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China.
- Hefei National Laboratory, Hefei, 230088, China.
- CAS Center of Excellence for Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, 100190, China.
- Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China.
| | - Heng Fan
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China.
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China.
- Hefei National Laboratory, Hefei, 230088, China.
- CAS Center of Excellence for Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, 100190, China.
- Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China.
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13
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Baykusheva DR, Kalthoff MH, Hofmann D, Claassen M, Kennes DM, Sentef MA, Mitrano M. Witnessing Nonequilibrium Entanglement Dynamics in a Strongly Correlated Fermionic Chain. PHYSICAL REVIEW LETTERS 2023; 130:106902. [PMID: 36962013 DOI: 10.1103/physrevlett.130.106902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 01/13/2023] [Accepted: 01/18/2023] [Indexed: 06/18/2023]
Abstract
Many-body entanglement in condensed matter systems can be diagnosed from equilibrium response functions through the use of entanglement witnesses and operator-specific quantum bounds. Here, we investigate the applicability of this approach for detecting entangled states in quantum systems driven out of equilibrium. We use a multipartite entanglement witness, the quantum Fisher information, to study the dynamics of a paradigmatic fermion chain undergoing a time-dependent change of the Coulomb interaction. Our results show that the quantum Fisher information is able to witness distinct signatures of multipartite entanglement both near and far from equilibrium that are robust against decoherence. We discuss implications of these findings for probing entanglement in light-driven quantum materials with time-resolved optical and x-ray scattering methods.
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Affiliation(s)
| | - Mona H Kalthoff
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free-Electron Laser Science (CFEL), Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Damian Hofmann
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free-Electron Laser Science (CFEL), Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Martin Claassen
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Dante M Kennes
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free-Electron Laser Science (CFEL), Luruper Chaussee 149, 22761 Hamburg, Germany
- Institut für Theorie der Statistischen Physik, RWTH Aachen University, 52056 Aachen, Germany and JARA-Fundamentals of Future Information Technology, 52056 Aachen, Germany
| | - Michael A Sentef
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free-Electron Laser Science (CFEL), Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Matteo Mitrano
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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14
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Yang Z, Ru S, Cao L, Zheludev N, Gao W. Experimental Demonstration of Quantum Overlapping Tomography. PHYSICAL REVIEW LETTERS 2023; 130:050804. [PMID: 36800476 DOI: 10.1103/physrevlett.130.050804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 11/08/2022] [Accepted: 01/13/2023] [Indexed: 06/18/2023]
Abstract
Quantum tomography is one of the major challenges of large-scale quantum information research due to the exponential time complexity. In this Letter, we develop and apply a Bayesian state estimation method to experimentally demonstrate quantum overlapping tomography [Phys. Rev. Lett. 124, 100401 (2020)PRLTAO0031-900710.1103/PhysRevLett.124.100401], a scheme intent on characterizing critical information of a many-body quantum system in logarithmic time complexity. By comparing the measurement results of full-state tomography and overlapping tomography, we show that overlapping tomography gives accurate information of the system with much fewer state measurements than full-state tomography.
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Affiliation(s)
- Zhengning Yang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Shihao Ru
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
- School of Physics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Lianzhen Cao
- School of Physics and Photoelectric Engineering, Weifang University, Weifang 261061, China
| | - Nikolay Zheludev
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
- The Photonics Institute and Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore 637371, Singapore
| | - Weibo Gao
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
- The Photonics Institute and Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore 637371, Singapore
- Center for Quantum Technologies, National University of Singapore, Singapore 117543, Singapore
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15
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Zhao SK, Ge ZY, Xiang Z, Xue GM, Yan HS, Wang ZT, Wang Z, Xu HK, Su FF, Yang ZH, Zhang H, Zhang YR, Guo XY, Xu K, Tian Y, Yu HF, Zheng DN, Fan H, Zhao SP. Probing Operator Spreading via Floquet Engineering in a Superconducting Circuit. PHYSICAL REVIEW LETTERS 2022; 129:160602. [PMID: 36306769 DOI: 10.1103/physrevlett.129.160602] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 08/09/2022] [Accepted: 08/11/2022] [Indexed: 06/16/2023]
Abstract
Operator spreading, often characterized by out-of-time-order correlators (OTOCs), is one of the central concepts in quantum many-body physics. However, measuring OTOCs is experimentally challenging due to the requirement of reversing the time evolution of systems. Here we apply Floquet engineering to investigate operator spreading in a superconducting 10-qubit chain. Floquet engineering provides an effective way to tune the coupling strength between nearby qubits, which is used to demonstrate quantum walks with tunable couplings, reversed time evolution, and the measurement of OTOCs. A clear light-cone-like operator propagation is observed in the system with multiple excitations, and has a nearly equal velocity as the single-particle quantum walk. For the butterfly operator that is nonlocal (local) under the Jordan-Wigner transformation, the OTOCs show distinct behaviors with (without) a signature of information scrambling in the near integrable system.
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Affiliation(s)
- S K Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Zi-Yong Ge
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Zhongcheng Xiang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - G M Xue
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - H S Yan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Z T Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Zhan Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - H K Xu
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - F F Su
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Z H Yang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - He Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Yu-Ran Zhang
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
| | - Xue-Yi Guo
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Kai Xu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
- CAS Center for Excellence in Topological Quantum Computation, UCAS, Beijing 100190, China
| | - Ye Tian
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - H F Yu
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - D N Zheng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
- CAS Center for Excellence in Topological Quantum Computation, UCAS, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan 523808, China
| | - Heng Fan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
- CAS Center for Excellence in Topological Quantum Computation, UCAS, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan 523808, China
| | - S P Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
- CAS Center for Excellence in Topological Quantum Computation, UCAS, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan 523808, China
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16
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Leng SY, Lü DY, Yang SL, Ma M, Dong YZ, Zhou BF, Zhou Y. Simulating the Dicke lattice model and quantum phase transitions using an array of coupled resonators. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:415402. [PMID: 35896108 DOI: 10.1088/1361-648x/ac84bd] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 07/27/2022] [Indexed: 06/15/2023]
Abstract
A proposal for simulating the Dicke-Lattice model in a mechanics-controlled hybrid quantum system is studied here. An array of coupled mechanical resonators (MRs) can homogeneously interact with a group of trapped Bose-Einstein condensates (BECs) via the gradient magnetic field induced by the oscillating resonators. Assisted by the classical dichromatic radio-wave fields, each subsystem with the BEC-MR interaction can mimic the Dicke type spin-phonon interaction, and the whole system is therefore extended to a lattice of Dicke models with the additional adjacent phonon-phonon hopping couplings. In view of this lattice model with theZ2symmetry, its quantum phase transitions behavior can be controlled by this periodic phonon-phonon interactions in the momentum space. This investigation may be considered as a fresh attempt on manipulating the critical behaviors of the collective spins through the external mechanical method.
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Affiliation(s)
- Si-Yun Leng
- School of Mathematics, Physics and Optoelectronic Engineering, Hubei University of Automotive Technology, Shiyan 442002, People's Republic of China
| | - Dong-Yan Lü
- School of Mathematics, Physics and Optoelectronic Engineering, Hubei University of Automotive Technology, Shiyan 442002, People's Republic of China
| | - Shuang-Liang Yang
- School of Mathematics, Physics and Optoelectronic Engineering, Hubei University of Automotive Technology, Shiyan 442002, People's Republic of China
| | - Ming Ma
- School of Electrical and Information Engineering, Hubei University of Automotive Technology, Shiyan 442002, People's Republic of China
| | - Yan-Zhang Dong
- School of Automobile Engineering, Hubei University of Automotive Technology, Shiyan 442002, People's Republic of China
| | - Bo-Fang Zhou
- School of Materials Science and Engineering, Hubei University of Automotive Technology, Shiyan 442002, People's Republic of China
| | - Yuan Zhou
- School of Mathematics, Physics and Optoelectronic Engineering, Hubei University of Automotive Technology, Shiyan 442002, People's Republic of China
- School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
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17
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Sajjan M, Li J, Selvarajan R, Sureshbabu SH, Kale SS, Gupta R, Singh V, Kais S. Quantum machine learning for chemistry and physics. Chem Soc Rev 2022; 51:6475-6573. [PMID: 35849066 DOI: 10.1039/d2cs00203e] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Machine learning (ML) has emerged as a formidable force for identifying hidden but pertinent patterns within a given data set with the objective of subsequent generation of automated predictive behavior. In recent years, it is safe to conclude that ML and its close cousin, deep learning (DL), have ushered in unprecedented developments in all areas of physical sciences, especially chemistry. Not only classical variants of ML, even those trainable on near-term quantum hardwares have been developed with promising outcomes. Such algorithms have revolutionized materials design and performance of photovoltaics, electronic structure calculations of ground and excited states of correlated matter, computation of force-fields and potential energy surfaces informing chemical reaction dynamics, reactivity inspired rational strategies of drug designing and even classification of phases of matter with accurate identification of emergent criticality. In this review we shall explicate a subset of such topics and delineate the contributions made by both classical and quantum computing enhanced machine learning algorithms over the past few years. We shall not only present a brief overview of the well-known techniques but also highlight their learning strategies using statistical physical insight. The objective of the review is not only to foster exposition of the aforesaid techniques but also to empower and promote cross-pollination among future research in all areas of chemistry which can benefit from ML and in turn can potentially accelerate the growth of such algorithms.
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Affiliation(s)
- Manas Sajjan
- Department of Chemistry, Purdue University, West Lafayette, IN-47907, USA. .,Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, Indiana 47907, USA
| | - Junxu Li
- Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, Indiana 47907, USA.,Department of Physics and Astronomy, Purdue University, West Lafayette, IN-47907, USA
| | - Raja Selvarajan
- Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, Indiana 47907, USA.,Department of Physics and Astronomy, Purdue University, West Lafayette, IN-47907, USA
| | - Shree Hari Sureshbabu
- Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, Indiana 47907, USA.,Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN-47907, USA
| | - Sumit Suresh Kale
- Department of Chemistry, Purdue University, West Lafayette, IN-47907, USA. .,Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, Indiana 47907, USA
| | - Rishabh Gupta
- Department of Chemistry, Purdue University, West Lafayette, IN-47907, USA. .,Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, Indiana 47907, USA
| | - Vinit Singh
- Department of Chemistry, Purdue University, West Lafayette, IN-47907, USA. .,Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, Indiana 47907, USA
| | - Sabre Kais
- Department of Chemistry, Purdue University, West Lafayette, IN-47907, USA. .,Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, Indiana 47907, USA.,Department of Physics and Astronomy, Purdue University, West Lafayette, IN-47907, USA.,Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN-47907, USA
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18
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Zhang X, Jiang W, Deng J, Wang K, Chen J, Zhang P, Ren W, Dong H, Xu S, Gao Y, Jin F, Zhu X, Guo Q, Li H, Song C, Gorshkov AV, Iadecola T, Liu F, Gong ZX, Wang Z, Deng DL, Wang H. Digital quantum simulation of Floquet symmetry-protected topological phases. Nature 2022; 607:468-473. [PMID: 35859194 PMCID: PMC9300455 DOI: 10.1038/s41586-022-04854-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 05/11/2022] [Indexed: 11/09/2022]
Abstract
Quantum many-body systems away from equilibrium host a rich variety of exotic phenomena that are forbidden by equilibrium thermodynamics. A prominent example is that of discrete time crystals1–8, in which time-translational symmetry is spontaneously broken in periodically driven systems. Pioneering experiments have observed signatures of time crystalline phases with trapped ions9,10, solid-state spin systems11–15, ultracold atoms16,17 and superconducting qubits18–20. Here we report the observation of a distinct type of non-equilibrium state of matter, Floquet symmetry-protected topological phases, which are implemented through digital quantum simulation with an array of programmable superconducting qubits. We observe robust long-lived temporal correlations and subharmonic temporal response for the edge spins over up to 40 driving cycles using a circuit of depth exceeding 240 and acting on 26 qubits. We demonstrate that the subharmonic response is independent of the initial state, and experimentally map out a phase boundary between the Floquet symmetry-protected topological and thermal phases. Our results establish a versatile digital simulation approach to exploring exotic non-equilibrium phases of matter with current noisy intermediate-scale quantum processors21. Signatures of non-equilibrium Floquet SPT phases with a programmable superconducting quantum processor are observed in which the discrete time translational symmetry only breaks at the boundaries and not in the bulk.
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Affiliation(s)
- Xu Zhang
- Department of Physics, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Interdisciplinary Center for Quantum Information, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Zhejiang University, Hangzhou, China
| | - Wenjie Jiang
- Center for Quantum Information, IIIS, Tsinghua University, Beijing, China
| | - Jinfeng Deng
- Department of Physics, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Interdisciplinary Center for Quantum Information, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Zhejiang University, Hangzhou, China
| | - Ke Wang
- Department of Physics, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Interdisciplinary Center for Quantum Information, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Zhejiang University, Hangzhou, China
| | - Jiachen Chen
- Department of Physics, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Interdisciplinary Center for Quantum Information, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Zhejiang University, Hangzhou, China
| | - Pengfei Zhang
- Department of Physics, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Interdisciplinary Center for Quantum Information, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Zhejiang University, Hangzhou, China
| | - Wenhui Ren
- Department of Physics, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Interdisciplinary Center for Quantum Information, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Zhejiang University, Hangzhou, China
| | - Hang Dong
- Department of Physics, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Interdisciplinary Center for Quantum Information, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Zhejiang University, Hangzhou, China
| | - Shibo Xu
- Department of Physics, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Interdisciplinary Center for Quantum Information, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Zhejiang University, Hangzhou, China
| | - Yu Gao
- Department of Physics, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Interdisciplinary Center for Quantum Information, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Zhejiang University, Hangzhou, China
| | - Feitong Jin
- Department of Physics, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Interdisciplinary Center for Quantum Information, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Zhejiang University, Hangzhou, China
| | - Xuhao Zhu
- Department of Physics, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Interdisciplinary Center for Quantum Information, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Zhejiang University, Hangzhou, China
| | - Qiujiang Guo
- Department of Physics, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Interdisciplinary Center for Quantum Information, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Zhejiang University, Hangzhou, China.,Alibaba-Zhejiang University Joint Research Institute of Frontier Technologies, Hangzhou, China
| | - Hekang Li
- Department of Physics, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Interdisciplinary Center for Quantum Information, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Zhejiang University, Hangzhou, China.,Alibaba-Zhejiang University Joint Research Institute of Frontier Technologies, Hangzhou, China
| | - Chao Song
- Department of Physics, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Interdisciplinary Center for Quantum Information, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Zhejiang University, Hangzhou, China.,Alibaba-Zhejiang University Joint Research Institute of Frontier Technologies, Hangzhou, China
| | - Alexey V Gorshkov
- Joint Quantum Institute and Joint Center for Quantum Information and Computer Science, University of Maryland and NIST, College Park, MD, USA
| | - Thomas Iadecola
- Department of Physics and Astronomy, Iowa State University, Ames, IA, USA.,Ames Laboratory, Ames, IA, USA
| | - Fangli Liu
- Joint Quantum Institute and Joint Center for Quantum Information and Computer Science, University of Maryland and NIST, College Park, MD, USA.,QuEra Computing Inc., Boston, MA, USA
| | - Zhe-Xuan Gong
- Department of Physics, Colorado School of Mines, Golden, CO, USA.,National Institute of Standards and Technology, Boulder, CO, USA
| | - Zhen Wang
- Department of Physics, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Interdisciplinary Center for Quantum Information, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Zhejiang University, Hangzhou, China. .,Alibaba-Zhejiang University Joint Research Institute of Frontier Technologies, Hangzhou, China.
| | - Dong-Ling Deng
- Center for Quantum Information, IIIS, Tsinghua University, Beijing, China. .,Shanghai Qi Zhi Institute, Shanghai, China.
| | - H Wang
- Department of Physics, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Interdisciplinary Center for Quantum Information, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Zhejiang University, Hangzhou, China.,Alibaba-Zhejiang University Joint Research Institute of Frontier Technologies, Hangzhou, China
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19
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Zhang K, Li H, Zhang P, Yuan J, Chen J, Ren W, Wang Z, Song C, Wang DW, Wang H, Zhu S, Agarwal GS, Scully MO. Synthesizing Five-Body Interaction in a Superconducting Quantum Circuit. PHYSICAL REVIEW LETTERS 2022; 128:190502. [PMID: 35622028 DOI: 10.1103/physrevlett.128.190502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 04/26/2022] [Indexed: 06/15/2023]
Abstract
Synthesizing many-body interaction Hamiltonians is a central task in quantum simulation. However, it is challenging to synthesize Hamiltonians that have more than two spins in a single term. Here we synthesize m-body spin-exchange Hamiltonians with m up to 5 in a superconducting quantum circuit by simultaneously exciting multiple independent qubits with time-energy correlated photons generated from a qudit. The dynamic evolution of the m-body interaction is governed by the Rabi oscillation between two m-spin states, in which the states of each spin are different. We demonstrate the scalability of our approach by comparing the influence of noises on the three-, four- and five-body interaction and building a many-body Mach-Zehnder interferometer which potentially has a Heisenberg-limit sensitivity. This study paves a way for quantum simulation involving many-body interaction Hamiltonians such as lattice gauge theories in quantum circuits.
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Affiliation(s)
- Ke Zhang
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Hekang Li
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Pengfei Zhang
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Jiale Yuan
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Jinyan Chen
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Wenhui Ren
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Zhen Wang
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Chao Song
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Da-Wei Wang
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
- CAS Center of Excellence in Topological Quantum Computation, Beijing 100190, China
| | - H Wang
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
- Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 311215, China
| | - Shiyao Zhu
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
- Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 311215, China
| | - Girish S Agarwal
- Institute of Quantum Science and Engineering, Texas A&M University, College Station, Texas 77843, USA
| | - Marlan O Scully
- Institute of Quantum Science and Engineering, Texas A&M University, College Station, Texas 77843, USA
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20
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Chen L, Xiu XM, Dong L, Liu NN, Shen CP, Zhang S, Chen S, Su SL. Direct conversion of Greenberger-Horne-Zeilinger state to Knill-Laflamme-Milburn state in decoherence-free subspace. OPTICS LETTERS 2022; 47:2262-2265. [PMID: 35486775 DOI: 10.1364/ol.458723] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 03/29/2022] [Indexed: 06/14/2023]
Abstract
Several schemes are proposed to realize the conversion of photonic polarized-entangled Greenberger-Horne-Zeilinger state to Knill-Laflamme-Milburn state in decoherence-free subspace (DFS) via weak cross-Kerr nonlinearity and X-quadrature homodyne measurement with high fidelity. DFS is introduced to decrease the decoherence effect caused by the coupling between the system and the environment. Optimizations to improve the success rate and utilization of residual states are further investigated. This study indicates important applications for quantum information processing in the future.
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21
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Xu K, Zhang YR, Sun ZH, Li H, Song P, Xiang Z, Huang K, Li H, Shi YH, Chen CT, Song X, Zheng D, Nori F, Wang H, Fan H. Metrological Characterization of Non-Gaussian Entangled States of Superconducting Qubits. PHYSICAL REVIEW LETTERS 2022; 128:150501. [PMID: 35499907 DOI: 10.1103/physrevlett.128.150501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 03/15/2022] [Indexed: 06/14/2023]
Abstract
Multipartite entangled states are significant resources for both quantum information processing and quantum metrology. In particular, non-Gaussian entangled states are predicted to achieve a higher sensitivity of precision measurements than Gaussian states. On the basis of metrological sensitivity, the conventional linear Ramsey squeezing parameter (RSP) efficiently characterizes the Gaussian entangled atomic states but fails for much wider classes of highly sensitive non-Gaussian states. These complex non-Gaussian entangled states can be classified by the nonlinear squeezing parameter (NLSP), as a generalization of the RSP with respect to nonlinear observables and identified via the Fisher information. However, the NLSP has never been measured experimentally. Using a 19-qubit programmable superconducting processor, we report the characterization of multiparticle entangled states generated during its nonlinear dynamics. First, selecting ten qubits, we measure the RSP and the NLSP by single-shot readouts of collective spin operators in several different directions. Then, by extracting the Fisher information of the time-evolved state of all 19 qubits, we observe a large metrological gain of 9.89_{-0.29}^{+0.28} dB over the standard quantum limit, indicating a high level of multiparticle entanglement for quantum-enhanced phase sensitivity. Benefiting from high-fidelity full controls and addressable single-shot readouts, the superconducting processor with interconnected qubits provides an ideal platform for engineering and benchmarking non-Gaussian entangled states that are useful for quantum-enhanced metrology.
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Affiliation(s)
- Kai Xu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yu-Ran Zhang
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
- RIKEN Center for Quantum Computing (RQC), Wako-shi, Saitama 351-0198, Japan
| | - Zheng-Hang Sun
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Hekang Li
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Pengtao Song
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Zhongcheng Xiang
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Kaixuan Huang
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Hao Li
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yun-Hao Shi
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Chi-Tong Chen
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiaohui Song
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Dongning Zheng
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Franco Nori
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
- RIKEN Center for Quantum Computing (RQC), Wako-shi, Saitama 351-0198, Japan
- Physics Department, University of Michigan, Ann Arbor, Michigan 48109-1040, USA
| | - H Wang
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Heng Fan
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Beijing Academy of Quantum Information Sciences and CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
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22
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Aguayo-Alvarado AL, Domínguez-Serna F, Cruz WDL, Garay-Palmett K. An integrated photonic circuit for color qubit preparation by third-order nonlinear interactions. Sci Rep 2022; 12:5154. [PMID: 35338208 PMCID: PMC8956746 DOI: 10.1038/s41598-022-09116-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 03/15/2022] [Indexed: 12/01/2022] Open
Abstract
This work presents a feasible design of an integrated photonic circuit performing as a device for single-qubit preparation and rotations through the third-order nonlinear process of difference frequency generation (DFG) and defined in the temporal mode basis. The first stage of our circuit includes the generation of heralded single photons by spontaneous four-wave mixing in a micro-ring cavity engineered for delivering a single-photon state in a unique temporal mode. The second stage comprises the implementation of DFG in a spiral waveguide with controlled dispersion properties for reaching color qubit preparation fidelity close to unity. We present the generalized rotation operator related to the DFG process, a methodology for the device design, and qubit preparation fidelity results as a function of user-accessible parameters.
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Affiliation(s)
- A L Aguayo-Alvarado
- Departamento de Óptica - Centro de Investigación Científica y de Educación Superior de, Ensenada, BC, 22860, México
| | - F Domínguez-Serna
- Cátedras Conacyt - Centro de Investigación Científica y de Educación Superior de, Ensenada, B.C., 22860, México
| | - W De La Cruz
- Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Km. 107 Carretera Tijuana-Ensenada, 22860, Ensenada, B.C., México
| | - K Garay-Palmett
- Departamento de Óptica - Centro de Investigación Científica y de Educación Superior de, Ensenada, BC, 22860, México.
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23
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Hasan MA, Runge K, Deymier PA. Experimental classical entanglement in a 16 acoustic qubit-analogue. Sci Rep 2021; 11:24248. [PMID: 34931009 PMCID: PMC8688442 DOI: 10.1038/s41598-021-03789-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 12/08/2021] [Indexed: 11/22/2022] Open
Abstract
The possibility of achieving and controlling scalable classically entangled, i.e., inseparable, multipartite states, would fundamentally challenge the advantages of quantum systems in harnessing the power of complexity in information science. Here, we investigate experimentally the extent of classical entanglement in a \documentclass[12pt]{minimal}
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\begin{document}$$16$$\end{document}16 acoustic qubit-analogue platform. The acoustic qubit-analogue, a.k.a., logical phi-bit, results from the spectral partitioning of the nonlinear acoustic field of externally driven coupled waveguides. Each logical phi-bit is a two-level subsystem characterized by two independently measurable phases. The phi-bits are co-located within the same physical space enabling distance independent interactions. We chose a vector state representation of the \documentclass[12pt]{minimal}
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\begin{document}$$16$$\end{document}16-phi-bit system which lies in a \documentclass[12pt]{minimal}
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\begin{document}$${2}^{16}$$\end{document}216-dimensional Hilbert space. The calculation of the entropy of entanglement demonstrates the possibility of achieving inseparability of the vector state and of navigating the corresponding Hilbert space. This work suggests a new direction in harnessing the complexity of classical inseparability in information science.
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Affiliation(s)
- M Arif Hasan
- Department of Mechanical Engineering, Wayne State University, Detroit, MI, 48202, USA.
| | - Keith Runge
- Department of Materials Science and Engineering, The University of Arizona, Tucson, AZ, 85721, USA
| | - Pierre A Deymier
- Department of Materials Science and Engineering, The University of Arizona, Tucson, AZ, 85721, USA
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24
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Bauer CW, Nachman B, Freytsis M. Simulating Collider Physics on Quantum Computers Using Effective Field Theories. PHYSICAL REVIEW LETTERS 2021; 127:212001. [PMID: 34860088 DOI: 10.1103/physrevlett.127.212001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 10/12/2021] [Indexed: 06/13/2023]
Abstract
Simulating the full dynamics of a quantum field theory over a wide range of energies requires exceptionally large quantum computing resources. Yet for many observables in particle physics, perturbative techniques are sufficient to accurately model all but a constrained range of energies within the validity of the theory. We demonstrate that effective field theories (EFTs) provide an efficient mechanism to separate the high energy dynamics that is easily calculated by traditional perturbation theory from the dynamics at low energy and show how quantum algorithms can be used to simulate the dynamics of the low energy EFT from first principles. As an explicit example we calculate the expectation values of vacuum-to-vacuum and vacuum-to-one-particle transitions in the presence of a time-ordered product of two Wilson lines in scalar field theory, an object closely related to those arising in EFTs of the standard model of particle physics. Calculations are performed using simulations of a quantum computer as well as measurements using the IBMQ Manhattan machine.
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Affiliation(s)
- Christian W Bauer
- Physics Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Benjamin Nachman
- Physics Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Marat Freytsis
- NHETC, Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA and Physics Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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25
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Gupta R, Levine RD, Kais S. Convergence of a Reconstructed Density Matrix to a Pure State Using the Maximal Entropy Approach. J Phys Chem A 2021; 125:7588-7595. [PMID: 34410718 DOI: 10.1021/acs.jpca.1c05884] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Impressive progress has been made in the past decade in the study of technological applications of varied types of quantum systems. With industry giants like IBM laying down their roadmap for scalable quantum devices with more than 1000-qubits by the end of 2023, efficient validation techniques are also being developed for testing quantum processing on these devices. The characterization of a quantum state is done by experimental measurements through the process called quantum state tomography (QST) which scales exponentially with the size of the system. However, QST performed using incomplete measurements is aptly suited for characterizing these quantum technologies especially with the current nature of noisy intermediate-scale quantum (NISQ) devices where not all mean measurements are available with high fidelity. We, hereby, propose an alternative approach to QST for the complete reconstruction of the density matrix of a quantum system in a pure state for any number of qubits by applying the maximal entropy formalism on the pairwise combinations of the known mean measurements. This approach provides the best estimate of the target state when we know the complete set of observables, which is the case of convergence of the reconstructed density matrix to a pure state. Our goal is to provide a practical inference of a quantum system in a pure state that can find its applications in the field of quantum error mitigation on a real quantum computer that we intend to investigate further.
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Affiliation(s)
- Rishabh Gupta
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Raphael D Levine
- The Fritz Haber Center for Molecular Dynamics and Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.,Department of Chemistry and Biochemistry and Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, California 90095, United States
| | - Sabre Kais
- Department of Chemistry, Department of Physics and Astronomy, and Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, Indiana 47907, United States
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26
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Jang W, Terashi K, Saito M, Bauer CW, Nachman B, Iiyama Y, Kishimoto T, Okubo R, Sawada R, Tanaka J. Quantum Gate Pattern Recognition and Circuit Optimization for Scientific Applications. EPJ WEB OF CONFERENCES 2021. [DOI: 10.1051/epjconf/202125103023] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
There is no unique way to encode a quantum algorithm into a quantum circuit. With limited qubit counts, connectivities, and coherence times, circuit optimization is essential to make the best use of quantum devices produced over a next decade. We introduce two separate ideas for circuit optimization and combine them in a multi-tiered quantum circuit optimization protocol called AQCEL. The first ingredient is a technique to recognize repeated patterns of quantum gates, opening up the possibility of future hardware optimization. The second ingredient is an approach to reduce circuit complexity by identifying zero- or low-amplitude computational basis states and redundant gates. As a demonstration, AQCEL is deployed on an iterative and effcient quantum algorithm designed to model final state radiation in high energy physics. For this algorithm, our optimization scheme brings a significant reduction in the gate count without losing any accuracy compared to the original circuit. Additionally, we have investigated whether this can be demonstrated on a quantum computer using polynomial resources. Our technique is generic and can be useful for a wide variety of quantum algorithms.
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27
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Biard H, Moreno-Pineda E, Ruben M, Bonet E, Wernsdorfer W, Balestro F. Increasing the Hilbert space dimension using a single coupled molecular spin. Nat Commun 2021; 12:4443. [PMID: 34290250 PMCID: PMC8295329 DOI: 10.1038/s41467-021-24693-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 04/30/2021] [Indexed: 11/09/2022] Open
Abstract
Quantum technologies are expected to introduce revolutionary changes in information processing in the near future. Nowadays, one of the main challenges is to be able to handle a large number of quantum bits (qubits), while preserving their quantum properties. Beyond the usual two-level encoding capacity of qubits, multi-level quantum systems are a promising way to extend and increase the amount of information that can be stored in the same number of quantum objects. Recent work (Kues et al. 2017), has shown the possibility to use devices based on photonic integrated circuits to entangle two qudits (with "d" being the number of available states). In the race to develop a mature quantum technology with real-world applications, many possible platforms are being investigated, including those that use photons, trapped ions, superconducting and silicon circuits and molecular magnets. In this work, we present the electronic read-out of a coupled molecular multi-level quantum systems, carried by a single Tb2Pc3 molecular magnet. Owning two magnetic centres, this molecular magnet architecture permits a 16 dimensions Hilbert space, opening the possibility of performing more complex quantum algorithms.
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Affiliation(s)
- Hugo Biard
- CNRS, Grenoble INP, Institut Néel, Univ. Grenoble Alpes, Grenoble, France
| | - Eufemio Moreno-Pineda
- Depto. de Química-Física, Escuela de Química, Facultad de Ciencias Naturales, Exactas y Tecnología, Universidad de Panamá, Panamá, Panamá
| | - Mario Ruben
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany.,Centre Européen de Sciences Quantiques (CESQ) within the Institut de Science et d'Ingénierie Supramoléculaires (ISIS), Strasbourg Cedex, France.,Institute for Quantum Materials and Technology (IQMT), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
| | - Edgar Bonet
- CNRS, Grenoble INP, Institut Néel, Univ. Grenoble Alpes, Grenoble, France
| | - Wolfgang Wernsdorfer
- CNRS, Grenoble INP, Institut Néel, Univ. Grenoble Alpes, Grenoble, France. .,Institute for Quantum Materials and Technology (IQMT), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany. .,Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany.
| | - Franck Balestro
- CNRS, Grenoble INP, Institut Néel, Univ. Grenoble Alpes, Grenoble, France.
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28
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Chen MC, Li Y, Liu RZ, Wu D, Su ZE, Wang XL, Li L, Liu NL, Lu CY, Pan JW. Directly Measuring a Multiparticle Quantum Wave Function via Quantum Teleportation. PHYSICAL REVIEW LETTERS 2021; 127:030402. [PMID: 34328769 DOI: 10.1103/physrevlett.127.030402] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 06/07/2021] [Indexed: 06/13/2023]
Abstract
We propose a new method to directly measure a general multiparticle quantum wave function, a single matrix element in a multi-particle density matrix, by quantum teleportation. The density matrix element is embedded in a virtual logical qubit and is nondestructively teleported to a single physical qubit for readout. We experimentally implement this method to directly measure the wave function of a photonic mixed quantum state beyond a single photon using a single observable for the first time. Our method also provides an exponential advantage over the standard quantum state tomography in measurement complexity to fully characterize a sparse multiparticle quantum state.
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Affiliation(s)
- Ming-Cheng Chen
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China and CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yuan Li
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China and CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Run-Ze Liu
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China and CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Dian Wu
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China and CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Zu-En Su
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China and CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xi-Lin Wang
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China and CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Li Li
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China and CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Nai-Le Liu
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China and CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Chao-Yang Lu
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China and CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jian-Wei Pan
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China and CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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29
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Quantum simulation of 2D antiferromagnets with hundreds of Rydberg atoms. Nature 2021; 595:233-238. [PMID: 34234335 DOI: 10.1038/s41586-021-03585-1] [Citation(s) in RCA: 86] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 04/27/2021] [Indexed: 11/08/2022]
Abstract
Quantum simulation using synthetic systems is a promising route to solve outstanding quantum many-body problems in regimes where other approaches, including numerical ones, fail1. Many platforms are being developed towards this goal, in particular based on trapped ions2-4, superconducting circuits5-7, neutral atoms8-11 or molecules12,13. All of these platforms face two key challenges: scaling up the ensemble size while retaining high-quality control over the parameters, and validating the outputs for these large systems. Here we use programmable arrays of individual atoms trapped in optical tweezers, with interactions controlled by laser excitation to Rydberg states11, to implement an iconic many-body problem-the antiferromagnetic two-dimensional transverse-field Ising model. We push this platform to a regime with up to 196 atoms manipulated with high fidelity and probe the antiferromagnetic order by dynamically tuning the parameters of the Hamiltonian. We illustrate the versatility of our platform by exploring various system sizes on two qualitatively different geometries-square and triangular arrays. We obtain good agreement with numerical calculations up to a computationally feasible size (approximately 100 particles). This work demonstrates that our platform can be readily used to address open questions in many-body physics.
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30
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Chen YJ, Chuu CS. Manipulation of multipartite entanglement in an array of quantum dots. OPTICS EXPRESS 2021; 29:19796-19806. [PMID: 34266082 DOI: 10.1364/oe.414803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 02/07/2021] [Indexed: 06/13/2023]
Abstract
Multipartite entanglement is indispensable in the implementation of quantum technologies and the fundamental test of quantum mechanics. Here we study how the W state and W-like state may be generated in a quantum-dot array by controlling the coupling between an incident photon and the quantum dots on a waveguide. We also discuss how the coupling may be controlled to observe the sudden death of entanglement. Our work can find potential applications in quantum information processing.
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31
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Cardani L, Valenti F, Casali N, Catelani G, Charpentier T, Clemenza M, Colantoni I, Cruciani A, D'Imperio G, Gironi L, Grünhaupt L, Gusenkova D, Henriques F, Lagoin M, Martinez M, Pettinari G, Rusconi C, Sander O, Tomei C, Ustinov AV, Weber M, Wernsdorfer W, Vignati M, Pirro S, Pop IM. Reducing the impact of radioactivity on quantum circuits in a deep-underground facility. Nat Commun 2021; 12:2733. [PMID: 33980835 PMCID: PMC8115287 DOI: 10.1038/s41467-021-23032-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 04/13/2021] [Indexed: 11/29/2022] Open
Abstract
As quantum coherence times of superconducting circuits have increased from nanoseconds to hundreds of microseconds, they are currently one of the leading platforms for quantum information processing. However, coherence needs to further improve by orders of magnitude to reduce the prohibitive hardware overhead of current error correction schemes. Reaching this goal hinges on reducing the density of broken Cooper pairs, so-called quasiparticles. Here, we show that environmental radioactivity is a significant source of nonequilibrium quasiparticles. Moreover, ionizing radiation introduces time-correlated quasiparticle bursts in resonators on the same chip, further complicating quantum error correction. Operating in a deep-underground lead-shielded cryostat decreases the quasiparticle burst rate by a factor thirty and reduces dissipation up to a factor four, showcasing the importance of radiation abatement in future solid-state quantum hardware.
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Affiliation(s)
| | - F Valenti
- PHI, Karlsruhe Institute of Technology, Karlsruhe, Germany
- IPE, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - N Casali
- INFN Sezione di Roma, Roma, Italy
| | - G Catelani
- JARA Institute for Quantum Information, Forschungszentrum Jülich, Jülich, Germany
| | - T Charpentier
- PHI, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - M Clemenza
- Dipartimento di Fisica, Università di Milano - Bicocca, Milano, Italy
- INFN Sezione di Milano - Bicocca, Milano, Italy
| | - I Colantoni
- INFN Sezione di Roma, Roma, Italy
- Istituto di Nanotecnologia, Consiglio Nazionale delle Ricerche, c/o Dip. Fisica, Sapienza Università di Roma, Roma, Italy
| | | | | | - L Gironi
- Dipartimento di Fisica, Università di Milano - Bicocca, Milano, Italy
- INFN Sezione di Milano - Bicocca, Milano, Italy
| | - L Grünhaupt
- PHI, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - D Gusenkova
- PHI, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - F Henriques
- PHI, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - M Lagoin
- PHI, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - M Martinez
- Fundación ARAID and Centro de Astropartículas y Física de Altas Energías, Universidad de Zaragoza, Zaragoza, Spain
| | - G Pettinari
- Institute for Photonics and Nanotechnologies, National Research Council, Rome, Italy
| | - C Rusconi
- INFN Laboratori Nazionali del Gran Sasso, Assergi, Italy
- Department of Physics and Astronomy, University of South Carolina, Columbia, USA
| | - O Sander
- IPE, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - C Tomei
- INFN Sezione di Roma, Roma, Italy
| | - A V Ustinov
- PHI, Karlsruhe Institute of Technology, Karlsruhe, Germany
- National University of Science and Technology MISIS, Moscow, Russia
- Russian Quantum Center, Skolkovo, Moscow, Russia
| | - M Weber
- IPE, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - W Wernsdorfer
- PHI, Karlsruhe Institute of Technology, Karlsruhe, Germany
- IQMT, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
- Institut Néel, CNRS and Université Joseph Fourier, Grenoble, France
| | - M Vignati
- INFN Sezione di Roma, Roma, Italy
- Dipartimento di Fisica, Sapienza Università di Roma, Roma, Italy
| | - S Pirro
- INFN Laboratori Nazionali del Gran Sasso, Assergi, Italy
| | - I M Pop
- PHI, Karlsruhe Institute of Technology, Karlsruhe, Germany.
- IQMT, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany.
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32
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Wang Z, Chen Y, Song Z, Qin D, Li H, Guo Q, Wang H, Song C, Li Y. Scalable Evaluation of Quantum-Circuit Error Loss Using Clifford Sampling. PHYSICAL REVIEW LETTERS 2021; 126:080501. [PMID: 33709761 DOI: 10.1103/physrevlett.126.080501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 01/12/2021] [Indexed: 06/12/2023]
Abstract
A major challenge in developing quantum computing technologies is to accomplish high precision tasks by utilizing multiplex optimization approaches, on both the physical system and algorithm levels. Loss functions assessing the overall performance of quantum circuits can provide the foundation for many optimization techniques. In this Letter, we use the quadratic error loss and the final-state fidelity loss to characterize quantum circuits. We find that the distribution of computation error is approximately Gaussian, which in turn justifies the quadratic error loss. It is shown that these loss functions can be efficiently evaluated in a scalable way by sampling from Clifford-dominated circuits. We demonstrate the results by numerically simulating 10-qubit noisy quantum circuits with various error models as well as executing 4-qubit circuits with up to ten layers of 2-qubit gates on a superconducting quantum processor. Our results pave the way toward the optimization-based quantum device and algorithm design in the intermediate-scale quantum regime.
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Affiliation(s)
- Zhen Wang
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Yanzhu Chen
- C. N. Yang Institute for Theoretical Physics, State University of New York at Stony Brook, Stony Brook, New York 11794-3840, USA
- Department of Physics and Astronomy, State University of New York at Stony Brook, Stony Brook, New York 11794-3800, USA
| | - Zixuan Song
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Dayue Qin
- Graduate School of China Academy of Engineering Physics, Beijing 100193, China
| | - Hekang Li
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Qiujiang Guo
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - H Wang
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Chao Song
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Ying Li
- Graduate School of China Academy of Engineering Physics, Beijing 100193, China
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33
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Zhang H, Su QP, Yang CP. Efficient scheme for creating a W-type optical entangled coherent state. OPTICS EXPRESS 2020; 28:35622-35635. [PMID: 33379674 DOI: 10.1364/oe.411810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 10/30/2020] [Indexed: 06/12/2023]
Abstract
W-type optical entangled coherent states have important applications in quantum communication. Previous works require performing measurement in the preparation of such W states. We here propose an efficient scheme for creating a W-type optical entangled coherent state without measurement. This scheme employs a setup composed of three microwave cavities and a superconducting flux coupler qutrit. Because no measurement is required, the W state can be generated deterministically. In addition, the system complexity is greatly reduced because of using only one qutrit to couple the three cavities. Numerical analysis shows that within current experimental technology, the W state can be prepared with high fidelity. This scheme is universal and can be extended to create the W-type optical entangled coherent state, by using three microwave or optical cavities coupled via a three-level natural or artificial atom.
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34
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Ma Y, Pan X, Cai W, Mu X, Xu Y, Hu L, Wang W, Wang H, Song YP, Yang ZB, Zheng SB, Sun L. Manipulating Complex Hybrid Entanglement and Testing Multipartite Bell Inequalities in a Superconducting Circuit. PHYSICAL REVIEW LETTERS 2020; 125:180503. [PMID: 33196232 DOI: 10.1103/physrevlett.125.180503] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 09/23/2020] [Indexed: 06/11/2023]
Abstract
Quantum correlations in observables of multiple systems not only are of fundamental interest, but also play a key role in quantum information processing. As a signature of these correlations, the violation of Bell inequalities has not been demonstrated with multipartite hybrid entanglement involving both continuous and discrete variables. Here we create a five-partite entangled state with three superconducting transmon qubits and two photonic qubits, each encoded in the mesoscopic field of a microwave cavity. We reveal the quantum correlations among these distinct elements by joint Wigner tomography of the two cavity fields conditional on the detection of the qubits and by test of a five-partite Bell inequality. The measured Bell signal is 8.381±0.038, surpassing the bound of 8 for a four-partite entanglement imposed by quantum correlations by 10 standard deviations, demonstrating the genuine five-partite entanglement in a hybrid quantum system.
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Affiliation(s)
- Y Ma
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
| | - X Pan
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
| | - W Cai
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
| | - X Mu
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
| | - Y Xu
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
| | - L Hu
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
| | - W Wang
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
| | - H Wang
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
| | - Y P Song
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
| | - Zhen-Biao Yang
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, Fujian 350108, China
| | - Shi-Biao Zheng
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, Fujian 350108, China
| | - L Sun
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
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35
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Gyongyosi L, Imre S. Circuit Depth Reduction for Gate-Model Quantum Computers. Sci Rep 2020; 10:11229. [PMID: 32641766 PMCID: PMC7343887 DOI: 10.1038/s41598-020-67014-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 05/13/2020] [Indexed: 11/18/2022] Open
Abstract
Quantum computers utilize the fundamentals of quantum mechanics to solve computational problems more efficiently than traditional computers. Gate-model quantum computers are fundamental to implement near-term quantum computer architectures and quantum devices. Here, a quantum algorithm is defined for the circuit depth reduction of gate-model quantum computers. The proposed solution evaluates the reduced time complexity equivalent of a reference quantum circuit. We prove the complexity of the quantum algorithm and the achievable reduction in circuit depth. The method provides a tractable solution to reduce the time complexity and physical layer costs of quantum computers.
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Affiliation(s)
- Laszlo Gyongyosi
- School of Electronics and Computer Science, University of Southampton, Southampton, SO17 1BJ, UK.
- Department of Networked Systems and Services, Budapest University of Technology and Economics, Budapest, H-1117, Hungary.
- MTA-BME Information Systems Research Group, Hungarian Academy of Sciences, Budapest, H-1051, Hungary.
| | - Sandor Imre
- Department of Networked Systems and Services, Budapest University of Technology and Economics, Budapest, H-1117, Hungary
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36
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Gyongyosi L. Unsupervised Quantum Gate Control for Gate-Model Quantum Computers. Sci Rep 2020; 10:10701. [PMID: 32612113 PMCID: PMC7329862 DOI: 10.1038/s41598-020-67018-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 05/11/2020] [Indexed: 12/03/2022] Open
Abstract
In near-term quantum computers, the operations are realized by unitary quantum gates. The precise and stable working mechanism of quantum gates is essential for the implementation of any complex quantum computations. Here, we define a method for the unsupervised control of quantum gates in near-term quantum computers. We model a scenario in which a tensor product structure of non-stable quantum gates is not controllable in terms of control theory. We prove that the non-stable quantum gate becomes controllable via a machine learning method if the quantum gates formulate an entangled gate structure.
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Affiliation(s)
- Laszlo Gyongyosi
- School of Electronics and Computer Science, University of Southampton, Southampton, SO17 1BJ, UK.
- Department of Networked Systems and Services, Budapest University of Technology and Economics, Budapest, H-1117, Hungary.
- MTA-BME Information Systems Research Group, Hungarian Academy of Sciences, Budapest, H-1051, Hungary.
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37
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Xu K, Sun ZH, Liu W, Zhang YR, Li H, Dong H, Ren W, Zhang P, Nori F, Zheng D, Fan H, Wang H. Probing dynamical phase transitions with a superconducting quantum simulator. SCIENCE ADVANCES 2020; 6:eaba4935. [PMID: 32596458 PMCID: PMC7299620 DOI: 10.1126/sciadv.aba4935] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 05/06/2020] [Indexed: 06/11/2023]
Abstract
Nonequilibrium quantum many-body systems, which are difficult to study via classical computation, have attracted wide interest. Quantum simulation can provide insights into these problems. Here, using a programmable quantum simulator with 16 all-to-all connected superconducting qubits, we investigate the dynamical phase transition in the Lipkin-Meshkov-Glick model with a quenched transverse field. Clear signatures of dynamical phase transitions, merging different concepts of dynamical criticality, are observed by measuring the nonequilibrium order parameter, nonlocal correlations, and the Loschmidt echo. Moreover, near the dynamical critical point, we obtain a spin squeezing of -7.0 ± 0.8 dB, showing multipartite entanglement, useful for measurements with precision fivefold beyond the standard quantum limit. On the basis of the capability of entangling qubits simultaneously and the accurate single-shot readout of multiqubit states, this superconducting quantum simulator can be used to study other problems in nonequilibrium quantum many-body systems, such as thermalization, many-body localization, and emergent phenomena in periodically driven systems.
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Affiliation(s)
- Kai Xu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Zheng-Hang Sun
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Wuxin Liu
- Interdisciplinary Centre for Quantum Information and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Yu-Ran Zhang
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
| | - Hekang Li
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Interdisciplinary Centre for Quantum Information and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Hang Dong
- Interdisciplinary Centre for Quantum Information and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Wenhui Ren
- Interdisciplinary Centre for Quantum Information and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Pengfei Zhang
- Interdisciplinary Centre for Quantum Information and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Franco Nori
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
- Physics Department, University of Michigan, Ann Arbor, MI 48109-1040, USA
| | - Dongning Zheng
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- CAS Centre for Excellence in Topological Quantum Computation, School of Physical Sciences, UCAS, Beijing 100190, China
| | - Heng Fan
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- CAS Centre for Excellence in Topological Quantum Computation, School of Physical Sciences, UCAS, Beijing 100190, China
| | - H. Wang
- Interdisciplinary Centre for Quantum Information and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
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38
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Stojanović VM. Bare-Excitation Ground State of a Spinless-Fermion-Boson Model and W-State Engineering in an Array of Superconducting Qubits and Resonators. PHYSICAL REVIEW LETTERS 2020; 124:190504. [PMID: 32469555 DOI: 10.1103/physrevlett.124.190504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 04/22/2020] [Indexed: 06/11/2023]
Abstract
This Letter unravels an interesting property of a one-dimensional lattice model that describes a single itinerant spinless fermion (excitation) coupled to zero-dimensional (dispersionless) bosons through two different nonlocal coupling mechanisms. Namely, below a critical value of the effective excitation-boson coupling strength, the exact ground state of this model is the zero-quasimomentum Bloch state of a bare (i.e., completely undressed) excitation. It is demonstrated here how this last property of the lattice model under consideration can be exploited for a fast, deterministic preparation of multipartite W states in a readily realizable system of inductively coupled superconducting qubits and microwave resonators.
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Affiliation(s)
- Vladimir M Stojanović
- Institut für Angewandte Physik, Technical University of Darmstadt, D-64289 Darmstadt, Germany
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39
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Song C, Xu K, Li H, Zhang YR, Zhang X, Liu W, Guo Q, Wang Z, Ren W, Hao J, Feng H, Fan H, Zheng D, Wang DW, Wang H, Zhu SY. Generation of multicomponent atomic Schrödinger cat states of up to 20 qubits. Science 2020; 365:574-577. [PMID: 31395779 DOI: 10.1126/science.aay0600] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 07/08/2019] [Indexed: 11/02/2022]
Abstract
Multipartite entangled states are crucial for numerous applications in quantum information science. However, the generation and verification of multipartite entanglement on fully controllable and scalable quantum platforms remains an outstanding challenge. We report the deterministic generation of an 18-qubit Greenberger-Horne-Zeilinger (GHZ) state and multicomponent atomic Schrödinger cat states of up to 20 qubits on a quantum processor, which features 20 superconducting qubits, also referred to as artificial atoms, interconnected by a bus resonator. By engineering a one-axis twisting Hamiltonian, the system of qubits, once initialized, coherently evolves to multicomponent atomic Schrödinger cat states-that is, superpositions of atomic coherent states including the GHZ state-at specific time intervals as expected. Our approach on a solid-state platform should not only stimulate interest in exploring the fundamental physics of quantum many-body systems, but also enable the development of applications in practical quantum metrology and quantum information processing.
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Affiliation(s)
- Chao Song
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Kai Xu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Hekang Li
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yu-Ran Zhang
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,Beijing Computational Science Research Center, Beijing 100094, China
| | - Xu Zhang
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Wuxin Liu
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Qiujiang Guo
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Zhen Wang
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Wenhui Ren
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Jie Hao
- Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
| | - Hui Feng
- Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
| | - Heng Fan
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China. .,CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Dongning Zheng
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China. .,CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Da-Wei Wang
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China.,CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
| | - H Wang
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China. .,Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Shi-Yao Zhu
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China.,Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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40
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Shettell N, Markham D. Graph States as a Resource for Quantum Metrology. PHYSICAL REVIEW LETTERS 2020; 124:110502. [PMID: 32242684 DOI: 10.1103/physrevlett.124.110502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 02/27/2020] [Indexed: 06/11/2023]
Abstract
By using highly entangled states, quantum metrology guarantees a precision impossible with classical measurements. Unfortunately such states can be very susceptible to noise, and it is a great challenge of the field to maintain quantum advantage in realistic conditions. In this Letter we investigate the practicality of graph states for quantum metrology. Graph states are a natural resource for much of quantum information, and here we characterize their quantum Fisher information for an arbitrary graph state. We then construct families of graph states which approximately achieves the Heisenberg limit, we call these states bundled graph states. We demonstrate that bundled graph states maintain a quantum advantage after being subjected to independent and identically distributed dephasing or finite erasures. This shows that these graph states are good resources for robust quantum metrology. We also quantify the number of n qubit stabilizer states that are useful as a resource for quantum metrology.
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Affiliation(s)
- Nathan Shettell
- Laboratoire dInformatique de Paris 6, CNRS, Sorbonne Universit, 4 place Jussieu, 75005 Paris, France
| | - Damian Markham
- Laboratoire dInformatique de Paris 6, CNRS, Sorbonne Universit, 4 place Jussieu, 75005 Paris, France
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41
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Omran A, Levine H, Keesling A, Semeghini G, Wang TT, Ebadi S, Bernien H, Zibrov AS, Pichler H, Choi S, Cui J, Rossignolo M, Rembold P, Montangero S, Calarco T, Endres M, Greiner M, Vuletić V, Lukin MD. Generation and manipulation of Schrödinger cat states in Rydberg atom arrays. Science 2020; 365:570-574. [PMID: 31395778 DOI: 10.1126/science.aax9743] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 07/08/2019] [Indexed: 11/03/2022]
Abstract
Quantum entanglement involving coherent superpositions of macroscopically distinct states is among the most striking features of quantum theory, but its realization is challenging because such states are extremely fragile. Using a programmable quantum simulator based on neutral atom arrays with interactions mediated by Rydberg states, we demonstrate the creation of "Schrödinger cat" states of the Greenberger-Horne-Zeilinger (GHZ) type with up to 20 qubits. Our approach is based on engineering the energy spectrum and using optimal control of the many-body system. We further demonstrate entanglement manipulation by using GHZ states to distribute entanglement to distant sites in the array, establishing important ingredients for quantum information processing and quantum metrology.
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Affiliation(s)
- A Omran
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - H Levine
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - A Keesling
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - G Semeghini
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - T T Wang
- Department of Physics, Harvard University, Cambridge, MA 02138, USA.,Department of Physics, Gordon College, Wenham, MA 01984, USA
| | - S Ebadi
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - H Bernien
- Institute for Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - A S Zibrov
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - H Pichler
- Department of Physics, Harvard University, Cambridge, MA 02138, USA.,Institute for Theoretical Atomic Molecular and Optical Physics (ITAMP), Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA
| | - S Choi
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA
| | - J Cui
- Forschungszentrum Jülich, Institute of Quantum Control (PGI-8), D-52425 Jülich, Germany
| | - M Rossignolo
- Institute for Quantum Optics and Center of Integrated Quantum Science and Technology (IQST), Universität Ulm, D-89081 Ulm, Germany
| | - P Rembold
- Forschungszentrum Jülich, Institute of Quantum Control (PGI-8), D-52425 Jülich, Germany
| | - S Montangero
- Dipartimento di Fisica e Astronomia "G. Galilei," Università degli Studi di Padova and Istituto Nazionale di Fisica Nucleare (INFN), I-35131 Padova, Italy
| | - T Calarco
- Forschungszentrum Jülich, Institute of Quantum Control (PGI-8), D-52425 Jülich, Germany.,Institute for Theoretical Physics, University of Cologne, D-50937 Cologne, Germany
| | - M Endres
- Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125, USA
| | - M Greiner
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - V Vuletić
- Department of Physics and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - M D Lukin
- Department of Physics, Harvard University, Cambridge, MA 02138, USA.
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42
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Cotler J, Wilczek F. Quantum Overlapping Tomography. PHYSICAL REVIEW LETTERS 2020; 124:100401. [PMID: 32216420 DOI: 10.1103/physrevlett.124.100401] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 02/10/2020] [Indexed: 06/10/2023]
Abstract
It is now experimentally possible to entangle thousands of qubits, and efficiently measure each qubit in parallel in a distinct basis. To fully characterize an unknown entangled state of n qubits, one requires an exponential number of measurements in n, which is experimentally unfeasible even for modest system sizes. By leveraging (i) that single-qubit measurements can be made in parallel, and (ii) the theory of perfect hash families, we show that all k-qubit reduced density matrices of an n qubit state can be determined with at most e^{O(k)}log^{2}(n) rounds of parallel measurements. We provide concrete measurement protocols which realize this bound. As an example, we argue that with near-term experiments, every two-point correlator in a system of 1024 qubits could be measured and completely characterized in a few days. This corresponds to determining nearly 4.5 million correlators.
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Affiliation(s)
- Jordan Cotler
- Stanford Institute for Theoretical Physics, Stanford University, Stanford, California 94305, USA
| | - Frank Wilczek
- Center for Theoretical Physics, MIT, Cambridge, Massachusetts 02139, USA
- T. D. Lee Institute, Shanghai, China
- Wilczek Quantum Center, Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- Department of Physics, Stockholm University, Stockholm, Sweden
- Department of Physics and Origins Project, Arizona State University, Tempe, Arizona 25287, USA
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43
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Gyongyosi L. Quantum State Optimization and Computational Pathway Evaluation for Gate-Model Quantum Computers. Sci Rep 2020; 10:4543. [PMID: 32161308 PMCID: PMC7066182 DOI: 10.1038/s41598-020-61316-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 02/25/2020] [Indexed: 11/09/2022] Open
Abstract
A computational problem fed into a gate-model quantum computer identifies an objective function with a particular computational pathway (objective function connectivity). The solution of the computational problem involves identifying a target objective function value that is the subject to be reached. A bottleneck in a gate-model quantum computer is the requirement of several rounds of quantum state preparations, high-cost run sequences, and multiple rounds of measurements to determine a target (optimal) state of the quantum computer that achieves the target objective function value. Here, we define a method for optimal quantum state determination and computational path evaluation for gate-model quantum computers. We prove a state determination method that finds a target system state for a quantum computer at a given target objective function value. The computational pathway evaluation procedure sets the connectivity of the objective function in the target system state on a fixed hardware architecture of the quantum computer. The proposed solution evolves the target system state without requiring the preparation of intermediate states between the initial and target states of the quantum computer. Our method avoids high-cost system state preparations and expensive running procedures and measurement apparatuses in gate-model quantum computers. The results are convenient for gate-model quantum computations and the near-term quantum devices of the quantum Internet.
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Affiliation(s)
- Laszlo Gyongyosi
- School of Electronics and Computer Science, University of Southampton, Southampton, SO17 1BJ, UK.
- Department of Networked Systems and Services, Budapest University of Technology and Economics, Budapest, H-1117, Hungary.
- MTA-BME Information Systems Research Group, Hungarian Academy of Sciences, Budapest, H-1051, Hungary.
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44
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A Simple Protocol for Certifying Graph States and Applications in Quantum Networks. CRYPTOGRAPHY 2020. [DOI: 10.3390/cryptography4010003] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We present a simple protocol for certifying graph states in quantum networks using stabiliser measurements. The certification statements can easily be applied to different protocols using graph states. We see, for example, how it can be used for measurement based verified quantum computation, certified sampling of random unitaries, quantum metrology and sharing quantum secrets over untrusted channels.
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45
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Wang Z, Li H, Feng W, Song X, Song C, Liu W, Guo Q, Zhang X, Dong H, Zheng D, Wang H, Wang DW. Controllable Switching between Superradiant and Subradiant States in a 10-qubit Superconducting Circuit. PHYSICAL REVIEW LETTERS 2020; 124:013601. [PMID: 31976713 DOI: 10.1103/physrevlett.124.013601] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Indexed: 06/10/2023]
Abstract
Superradiance and subradiance concerning enhanced and inhibited collective radiation of an ensemble of atoms have been a central topic in quantum optics. However, precise generation and control of these states remain challenging. Here we deterministically generate up to 10-qubit superradiant and 8-qubit subradiant states, each containing a single excitation, in a superconducting quantum circuit with multiple qubits interconnected by a cavity resonator. The sqrt[N]-scaling enhancement of the coupling strength between the superradiant states and the cavity is validated. By applying an appropriate phase gate on each qubit, we are able to switch the single collective excitation between superradiant and subradiant states. While the subradiant states containing a single excitation are forbidden from emitting photons, we demonstrate that they can still absorb photons from the resonator. However, for an even number of qubits, a singlet state with half of the qubits being excited can neither emit nor absorb photons, which is verified with 4 qubits. This study is a step forward in coherent control of collective radiation and has promising applications in quantum information processing.
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Affiliation(s)
- Zhen Wang
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Hekang Li
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Wei Feng
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Xiaohui Song
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Chao Song
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Wuxin Liu
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Qiujiang Guo
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Xu Zhang
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Hang Dong
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Dongning Zheng
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
| | - H Wang
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Da-Wei Wang
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
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46
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Ren H, Li Y. Modeling Quantum Devices and the Reconstruction of Physics in Practical Systems. PHYSICAL REVIEW LETTERS 2019; 123:140405. [PMID: 31702201 DOI: 10.1103/physrevlett.123.140405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 08/06/2019] [Indexed: 06/10/2023]
Abstract
Modeling quantum devices is to find a model according to quantum theory that can explain the result of experiments in a quantum device. We find that usually we cannot correctly identify the model describing the actual physics of the device, regardless of the experimental effort, given a limited set of operations. According to sufficient conditions that we find, correctly reconstructing the model requires either a particular set of pure states and projective measurements or a set of evolution operators that can generate all unitary operators.
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Affiliation(s)
- Hang Ren
- School of Physics, Nankai University, Tianjin 300071, China
| | - Ying Li
- Graduate School of China Academy of Engineering Physics, Beijing 100193, China
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47
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Entanglement in a 20-Qubit Superconducting Quantum Computer. Sci Rep 2019; 9:13465. [PMID: 31530848 PMCID: PMC6748943 DOI: 10.1038/s41598-019-49805-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 08/23/2019] [Indexed: 11/17/2022] Open
Abstract
The ability to prepare sizeable multi-qubit entangled states with full qubit control is a critical milestone for physical platforms upon which quantum computers are built. We investigate the extent to which entanglement is found within a prepared graph state on the 20-qubit superconducting quantum computer IBM Q Poughkeepsie. We prepared a graph state along a path consisting of all twenty qubits within the device and performed full quantum state tomography on all groups of four connected qubits along this path. We determined that each pair of connected qubits was inseparable and hence the prepared state was entangled. Additionally, a genuine multipartite entanglement witness was measured on all qubit subpaths of the graph state and we found genuine multipartite entanglement on chains of up to three qubits. These results represent a demonstration of entanglement in one of the largest solid-state qubit arrays to date and indicate the positive direction of progress towards the goal of implementing complex quantum algorithms relying on such effects.
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48
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Realization of efficient quantum gates with a superconducting qubit-qutrit circuit. Sci Rep 2019; 9:13389. [PMID: 31527726 PMCID: PMC6746868 DOI: 10.1038/s41598-019-49657-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 08/08/2019] [Indexed: 11/25/2022] Open
Abstract
Building a quantum computer is a daunting challenge since it requires good control but also good isolation from the environment to minimize decoherence. It is therefore important to realize quantum gates efficiently, using as few operations as possible, to reduce the amount of required control and operation time and thus improve the quantum state coherence. Here we propose a superconducting circuit for implementing a tunable system consisting of a qutrit coupled to two qubits. This system can efficiently accomplish various quantum information tasks, including generation of entanglement of the two qubits and conditional three-qubit quantum gates, such as the Toffoli and Fredkin gates. Furthermore, the system realizes a conditional geometric gate which may be used for holonomic (non-adiabatic) quantum computing. The efficiency, robustness and universality of the presented circuit makes it a promising candidate to serve as a building block for larger networks capable of performing involved quantum computational tasks.
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49
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Song C, Cui J, Wang H, Hao J, Feng H, Li Y. Quantum computation with universal error mitigation on a superconducting quantum processor. SCIENCE ADVANCES 2019; 5:eaaw5686. [PMID: 31523709 PMCID: PMC6731091 DOI: 10.1126/sciadv.aaw5686] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Accepted: 08/06/2019] [Indexed: 06/10/2023]
Abstract
Medium-scale quantum devices that integrate about hundreds of physical qubits are likely to be developed in the near future. However, these devices will lack the resources for realizing quantum fault tolerance. Therefore, the main challenge of exploring the advantage of quantum computation is to minimize the impact of device and control imperfections without complete logical encoding. Quantum error mitigation is a solution satisfying the requirement. Here, we demonstrate an error mitigation protocol based on gate set tomography and quasi-probability decomposition. One- and two-qubit circuits are tested on a superconducting device, and computation errors are successfully suppressed. Because this protocol is universal for digital quantum computers and algorithms computing expected values, our results suggest that error mitigation can be an essential component of near-future quantum computation.
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Affiliation(s)
- Chao Song
- Interdisciplinary Center for Quantum Information and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Jing Cui
- Interdisciplinary Center for Quantum Information and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - H. Wang
- Interdisciplinary Center for Quantum Information and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - J. Hao
- Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
| | - H. Feng
- Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
| | - Ying Li
- Graduate School of China Academy of Engineering Physics, Beijing 100193, China
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50
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