1
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Bond LJ, Safavi-Naini A, Minář J. Fast Quantum State Preparation and Bath Dynamics Using Non-Gaussian Variational Ansatz and Quantum Optimal Control. PHYSICAL REVIEW LETTERS 2024; 132:170401. [PMID: 38728702 DOI: 10.1103/physrevlett.132.170401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 01/15/2024] [Accepted: 03/25/2024] [Indexed: 05/12/2024]
Abstract
Fast preparation of quantum many-body states is essential for myriad quantum algorithms and metrological applications. Here, we develop a new pathway for fast, nonadiabatic preparation of quantum many-body states that combines quantum optimal control with a variational Ansatz based on non-Gaussian states. We demonstrate our approach on the spin-boson model, a single spin interacting with the bath. We use a multipolaron Ansatz to prepare near-critical ground states. For one mode, we achieve a reduction in infidelity of up to ≈60 (≈10) times compared to linear (optimized local adiabatic) ramps; for many modes, we achieve a reduction in infidelity of up to ≈5 times compared to nonadiabatic linear ramps. Further, we show that the typical control quantity, the leakage from the variational manifold, provides only a loose bound on the state's fidelity. Instead, in analogy to the bond dimension of matrix product states, we suggest a controlled convergence criterion based on the number of polarons. Finally, motivated by the possibility of realizations in trapped ions, we study the dynamics of a system with bath properties going beyond the paradigm of (sub- and/or super-) Ohmic couplings.
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Affiliation(s)
- Liam J Bond
- Institute for Theoretical Physics, Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
- QuSoft, Science Park 123, 1098 XG Amsterdam, The Netherlands
| | - Arghavan Safavi-Naini
- Institute for Theoretical Physics, Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
- QuSoft, Science Park 123, 1098 XG Amsterdam, The Netherlands
| | - Jiří Minář
- Institute for Theoretical Physics, Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
- QuSoft, Science Park 123, 1098 XG Amsterdam, The Netherlands
- CWI, Science Park 904, 1098 XH Amsterdam, The Netherlands
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2
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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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3
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Gutman N, Gorlach A, Tziperman O, Ruimy R, Kaminer I. Universal Control of Symmetric States Using Spin Squeezing. PHYSICAL REVIEW LETTERS 2024; 132:153601. [PMID: 38682988 DOI: 10.1103/physrevlett.132.153601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Accepted: 03/11/2024] [Indexed: 05/01/2024]
Abstract
The manipulation of quantum many-body systems is a crucial goal in quantum science. Entangled quantum states that are symmetric under qubits permutation are of growing interest. Yet, the creation and control of symmetric states has remained a challenge. Here, we introduce a method to universally control symmetric states, proposing a scheme that relies solely on coherent rotations and spin squeezing. We present protocols for the creation of different symmetric states including Schrödinger's cat and Gottesman-Kitaev-Preskill states. The obtained symmetric states can be transferred to traveling photonic states via spontaneous emission, providing a powerful approach for engineering desired quantum photonic states.
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Affiliation(s)
- Nir Gutman
- Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Alexey Gorlach
- Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Offek Tziperman
- Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Ron Ruimy
- Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Ido Kaminer
- Technion-Israel Institute of Technology, Haifa 32000, Israel
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4
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Huang J, Li X, Chen X, Zhai C, Zheng Y, Chi Y, Li Y, He Q, Gong Q, Wang J. Demonstration of hypergraph-state quantum information processing. Nat Commun 2024; 15:2601. [PMID: 38521765 PMCID: PMC10960808 DOI: 10.1038/s41467-024-46830-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 03/12/2024] [Indexed: 03/25/2024] Open
Abstract
Complex entangled states are the key resources for measurement-based quantum computations, which is realised by performing a sequence of measurements on initially entangled qubits. Executable quantum algorithms in the graph-state quantum computing model are determined by the entanglement structure and the connectivity of entangled qubits. By generalisation from graph-type entanglement in which only the nearest qubits interact to a new type of hypergraph entanglement in which any subset of qubits can be arbitrarily entangled via hyperedges, hypergraph states represent more general resource states that allow arbitrary quantum computation with Pauli universality. Here we report experimental preparation, certification and processing of complete categories of four-qubit hypergraph states under the principle of local unitary equivalence, on a fully reprogrammable silicon-photonic quantum chip. Genuine multipartite entanglement for hypergraph states is certificated by the characterisation of entanglement witness, and the observation of violations of Mermin inequalities without any closure of distance or detection loopholes. A basic measurement-based protocol and an efficient resource state verification by color-encoding stabilizers are implemented with local Pauli measurement to benchmark the building blocks for hypergraph-state quantum computation. Our work prototypes hypergraph entanglement as a general resource for quantum information processing.
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Affiliation(s)
- Jieshan Huang
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China
| | - Xudong Li
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Xiaojiong Chen
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China
| | - Chonghao Zhai
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China
| | - Yun Zheng
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China
| | - Yulin Chi
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China
| | - Yan Li
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China
- Frontiers Science Center for Nano-optoelectronics and Collaborative Innovation Center of Quantum Matter, Peking University, 100871, Beijing, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, Shanxi, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, 226010, Jiangsu, China
- Hefei National Laboratory, Hefei, 230088, China
| | - Qiongyi He
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China
- Frontiers Science Center for Nano-optoelectronics and Collaborative Innovation Center of Quantum Matter, Peking University, 100871, Beijing, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, Shanxi, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, 226010, Jiangsu, China
- Hefei National Laboratory, Hefei, 230088, China
| | - Qihuang Gong
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China
- Frontiers Science Center for Nano-optoelectronics and Collaborative Innovation Center of Quantum Matter, Peking University, 100871, Beijing, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, Shanxi, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, 226010, Jiangsu, China
- Hefei National Laboratory, Hefei, 230088, China
| | - Jianwei Wang
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China.
- Frontiers Science Center for Nano-optoelectronics and Collaborative Innovation Center of Quantum Matter, Peking University, 100871, Beijing, China.
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, Shanxi, China.
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, 226010, Jiangsu, China.
- Hefei National Laboratory, Hefei, 230088, China.
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5
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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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6
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Niu J, Li Y, Zhang L, Zhang J, Chu J, Huang J, Huang W, Nie L, Qiu J, Sun X, Tao Z, Wei W, Zhang J, Zhou Y, Chen Y, Hu L, Liu Y, Liu S, Zhong Y, Lu D, Yu D. Demonstrating Path-Independent Anyonic Braiding on a Modular Superconducting Quantum Processor. PHYSICAL REVIEW LETTERS 2024; 132:020601. [PMID: 38277590 DOI: 10.1103/physrevlett.132.020601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 11/22/2023] [Accepted: 12/01/2023] [Indexed: 01/28/2024]
Abstract
Anyons, exotic quasiparticles in two-dimensional space exhibiting nontrivial exchange statistics, play a crucial role in universal topological quantum computing. One notable proposal to manifest the fractional statistics of anyons is the toric code model; however, scaling up its size through quantum simulation poses a serious challenge because of its highly entangled ground state. In this Letter, we demonstrate that a modular superconducting quantum processor enables hardware-pragmatic implementation of the toric code model. Through in-parallel control across separate modules, we generate a 10-qubit toric code ground state in four steps and realize six distinct braiding paths to benchmark the performance of anyonic statistics. The path independence of the anyonic braiding statistics is verified by correlation measurements in an efficient and scalable fashion. Our modular approach, serving as a hardware embodiment of the toric code model, offers a promising avenue toward scalable simulation of topological phases, paving the way for quantum simulation in a distributed fashion.
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Affiliation(s)
- Jingjing Niu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- Shenzhen Branch, Hefei National Laboratory, Shenzhen 518048, China
| | - Yishan Li
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Libo Zhang
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jiajian Zhang
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Ji Chu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jiaxiang Huang
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Wenhui Huang
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Lifu Nie
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jiawei Qiu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xuandong Sun
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Ziyu Tao
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Weiwei Wei
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jiawei Zhang
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yuxuan Zhou
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yuanzhen Chen
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Ling Hu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yang Liu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Song Liu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- Shenzhen Branch, Hefei National Laboratory, Shenzhen 518048, China
| | - Youpeng Zhong
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- Shenzhen Branch, Hefei National Laboratory, Shenzhen 518048, China
| | - Dawei Lu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Dapeng Yu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- Shenzhen Branch, Hefei National Laboratory, Shenzhen 518048, China
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
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7
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Fulton J, Thenabadu M, Teh RY, Reid MD. Weak versus Deterministic Macroscopic Realism, and Einstein-Podolsky-Rosen's Elements of Reality. ENTROPY (BASEL, SWITZERLAND) 2023; 26:11. [PMID: 38275490 PMCID: PMC11154650 DOI: 10.3390/e26010011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 10/25/2023] [Accepted: 11/13/2023] [Indexed: 01/27/2024]
Abstract
The violation of a Leggett-Garg inequality confirms the incompatibility between quantum mechanics and the combined premises (called macro-realism) of macroscopic realism (MR) and noninvasive measurability (NIM). Arguments can be given that the incompatibility arises because MR fails for systems in a superposition of macroscopically distinct states-or else, that NIM fails. In this paper, we consider a strong negation of macro-realism, involving superpositions of coherent states, where the NIM premise is replaced by Bell's locality premise. We follow recent work and propose the validity of a subset of Einstein-Podolsky-Rosen (EPR) and Leggett-Garg premises, referred to as weak macroscopic realism (wMR). In finding consistency with wMR, we identify that the Leggett-Garg inequalities are violated because of failure of both MR and NIM, but also that both are valid in a weaker (less restrictive) sense. Weak MR is distinguished from deterministic macroscopic realism (dMR) by recognizing that a measurement involves a reversible unitary interaction that establishes the measurement setting. Weak MR posits that a predetermined value for the outcome of a measurement can be attributed to the system after the interaction, when the measurement setting is experimentally specified. An extended definition of wMR considers the "element of reality" defined by EPR for system A, where one can predict with certainty the outcome of a measurement on A by performing a measurement on system B. Weak MR posits that this element of reality exists once the unitary interaction determining the measurement setting at B has occurred. We demonstrate compatibility of systems violating Leggett-Garg inequalities with wMR but point out that dMR has been shown to be falsifiable. Other tests of wMR are proposed, the predictions of wMR agreeing with quantum mechanics. Finally, we compare wMR with macro-realism models discussed elsewhere. An argument in favour of wMR is presented: wMR resolves a potential contradiction pointed out by Leggett and Garg between failure of macro-realism and assumptions intrinsic to quantum measurement theory.
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Affiliation(s)
| | | | | | - Margaret D. Reid
- Centre for Quantum Science and Technology Theory, Swinburne University of Technology, Melbourne 3122, Australia; (J.F.); (M.T.); (R.Y.T.)
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8
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Hatharasinghe C, Thenabadu M, Drummond PD, Reid MD. A Macroscopic Quantum Three-Box Paradox: Finding Consistency with Weak Macroscopic Realism. ENTROPY (BASEL, SWITZERLAND) 2023; 25:1620. [PMID: 38136500 PMCID: PMC10742550 DOI: 10.3390/e25121620] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 10/24/2023] [Accepted: 10/27/2023] [Indexed: 12/24/2023]
Abstract
The quantum three-box paradox considers a ball prepared in a superposition of being in any one of three boxes. Bob makes measurements by opening either box 1 or box 2. After performing some unitary operations (shuffling), Alice can infer with certainty that the ball was detected by Bob, regardless of which box he opened, if she detects the ball after opening box 3. The paradox is that the ball would have been found with certainty by Bob in either box if that box had been opened. Resolutions of the paradox include that Bob's measurement cannot be made non-invasively or else that realism cannot be assumed at the quantum level. Here, we strengthen the case for the former argument by constructing macroscopic versions of the paradox. Macroscopic realism implies that the ball is in one of the boxes prior to Bob or Alice opening any boxes. We demonstrate the consistency of the paradox with macroscopic realism, if carefully defined (as weak macroscopic realism, wMR) to apply to the system at the times prior to Alice or Bob opening any boxes but after the unitary operations associated with preparation or shuffling. By solving for the dynamics of the unitary operations and comparing with mixed states, we demonstrate agreement between the predictions of wMR and quantum mechanics: the paradox only manifests if Alice's shuffling combines both local operations (on box 3) and nonlocal operations, on the other boxes. Following previous work, the macroscopic paradox is shown to correspond to a violation of a Leggett-Garg inequality, which implies failure of non-invasive measurability if wMR holds.
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Affiliation(s)
| | | | | | - Margaret D. Reid
- Center for Quantum Science and Technology Theory, Swinburne University of Technology, Melbourne 3122, Australia (P.D.D.)
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9
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Zhang C, Yu P, Jadbabaie A, Hutzler NR. Quantum-Enhanced Metrology for Molecular Symmetry Violation Using Decoherence-Free Subspaces. PHYSICAL REVIEW LETTERS 2023; 131:193602. [PMID: 38000409 DOI: 10.1103/physrevlett.131.193602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 10/12/2023] [Indexed: 11/26/2023]
Abstract
We propose a method to measure time-reversal symmetry violation in molecules that overcomes the standard quantum limit while leveraging decoherence-free subspaces to mitigate sensitivity to classical noise. The protocol does not require an external electric field, and the entangled states have no first-order sensitivity to static electromagnetic fields as they involve superpositions with zero average lab-frame projection of spins and dipoles. This protocol can be applied with trapped neutral or ionic species, and can be implemented using methods that have been demonstrated experimentally.
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Affiliation(s)
- Chi Zhang
- California Institute of Technology, Division of Physics, Mathematics, and Astronomy, Pasadena, California 91125, USA
| | - Phelan Yu
- California Institute of Technology, Division of Physics, Mathematics, and Astronomy, Pasadena, California 91125, USA
| | - Arian Jadbabaie
- California Institute of Technology, Division of Physics, Mathematics, and Astronomy, Pasadena, California 91125, USA
| | - Nicholas R Hutzler
- California Institute of Technology, Division of Physics, Mathematics, and Astronomy, Pasadena, California 91125, USA
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10
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Scholl P, Shaw AL, Tsai RBS, Finkelstein R, Choi J, Endres M. Erasure conversion in a high-fidelity Rydberg quantum simulator. Nature 2023; 622:273-278. [PMID: 37821592 PMCID: PMC10567575 DOI: 10.1038/s41586-023-06516-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 08/03/2023] [Indexed: 10/13/2023]
Abstract
Minimizing and understanding errors is critical for quantum science, both in noisy intermediate scale quantum (NISQ) devices1 and for the quest towards fault-tolerant quantum computation2,3. Rydberg arrays have emerged as a prominent platform in this context4 with impressive system sizes5,6 and proposals suggesting how error-correction thresholds could be significantly improved by detecting leakage errors with single-atom resolution7,8, a form of erasure error conversion9-12. However, two-qubit entanglement fidelities in Rydberg atom arrays13,14 have lagged behind competitors15,16 and this type of erasure conversion is yet to be realized for matter-based qubits in general. Here we demonstrate both erasure conversion and high-fidelity Bell state generation using a Rydberg quantum simulator5,6,17,18. When excising data with erasure errors observed via fast imaging of alkaline-earth atoms19-22, we achieve a Bell state fidelity of [Formula: see text], which improves to [Formula: see text] when correcting for remaining state-preparation errors. We further apply erasure conversion in a quantum simulation experiment for quasi-adiabatic preparation of long-range order across a quantum phase transition, and reveal the otherwise hidden impact of these errors on the simulation outcome. Our work demonstrates the capability for Rydberg-based entanglement to reach fidelities in the 0.999 regime, with higher fidelities a question of technical improvements, and shows how erasure conversion can be utilized in NISQ devices. These techniques could be translated directly to quantum-error-correction codes with the addition of long-lived qubits7,22-24.
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Affiliation(s)
- Pascal Scholl
- California Institute of Technology, Pasadena, CA, USA
| | - Adam L Shaw
- California Institute of Technology, Pasadena, CA, USA
| | | | | | - Joonhee Choi
- California Institute of Technology, Pasadena, CA, USA
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Manuel Endres
- California Institute of Technology, Pasadena, CA, USA.
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11
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Bharti V, Sugawa S, Mizoguchi M, Kunimi M, Zhang Y, de Léséleuc S, Tomita T, Franz T, Weidemüller M, Ohmori K. Picosecond-Scale Ultrafast Many-Body Dynamics in an Ultracold Rydberg-Excited Atomic Mott Insulator. PHYSICAL REVIEW LETTERS 2023; 131:123201. [PMID: 37802940 DOI: 10.1103/physrevlett.131.123201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 07/06/2022] [Accepted: 08/03/2023] [Indexed: 10/08/2023]
Abstract
We report the observation and control of ultrafast many-body dynamics of electrons in ultracold Rydberg-excited atoms, spatially ordered in a three-dimensional Mott insulator (MI) with unity filling in an optical lattice. By mapping out the time-domain Ramsey interferometry in the picosecond timescale, we can deduce entanglement growth indicating the emergence of many-body correlations via dipolar forces. We analyze our observations with different theoretical approaches and find that the semiclassical model breaks down, thus indicating that quantum fluctuations play a decisive role in the observed dynamics. Combining picosecond Rydberg excitation with MI lattice thus provides a platform for simulating nonequilibrium dynamics of strongly correlated systems in synthetic ultracold atomic crystals, such as in a metal-like quantum gas regime.
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Affiliation(s)
- V Bharti
- Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki 444-8585, Japan
| | - S Sugawa
- Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki 444-8585, Japan
- SOKENDAI (The Graduate University for Advanced Studies), Okazaki 444-8585, Japan
| | - M Mizoguchi
- Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki 444-8585, Japan
| | - M Kunimi
- Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki 444-8585, Japan
| | - Y Zhang
- Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki 444-8585, Japan
- College of Physics and Electronic Engineering, and Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - S de Léséleuc
- Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki 444-8585, Japan
- SOKENDAI (The Graduate University for Advanced Studies), Okazaki 444-8585, Japan
| | - T Tomita
- Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki 444-8585, Japan
| | - T Franz
- Physikalisches Institut, Universität Heidelberg, Im Neuenheimer Feld 226, 69120 Heidelberg, Germany
| | - M Weidemüller
- Physikalisches Institut, Universität Heidelberg, Im Neuenheimer Feld 226, 69120 Heidelberg, Germany
| | - K Ohmori
- Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki 444-8585, Japan
- SOKENDAI (The Graduate University for Advanced Studies), Okazaki 444-8585, Japan
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12
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Lee JY, Ramette J, Metlitski MA, Vuletić V, Ho WW, Choi S. Landau-Forbidden Quantum Criticality in Rydberg Quantum Simulators. PHYSICAL REVIEW LETTERS 2023; 131:083601. [PMID: 37683144 DOI: 10.1103/physrevlett.131.083601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 11/27/2022] [Accepted: 07/31/2023] [Indexed: 09/10/2023]
Abstract
The Landau-Ginzburg-Wilson theory of phase transitions precludes a continuous transition between two phases that spontaneously break distinct symmetries. However, quantum mechanical effects can intertwine the symmetries, giving rise to an exotic phenomenon called deconfined quantum criticality (DQC). In this Letter, we study the ground state phase diagram of a one-dimensional array of individually trapped neutral atoms interacting strongly via Rydberg states, and demonstrate through extensive numerical simulations that it hosts a variety of symmetry-breaking phases and their transitions including DQC. We show how an enlarged, emergent continuous symmetry arises at the DQCs, which can be experimentally observed in the joint distribution of two distinct order parameters, obtained within measurement snapshots in the standard computational basis. Our findings highlight quantum simulators of Rydberg atoms not only as promising platforms to experimentally realize such exotic phenomena, but also as unique ones allowing access to physical properties not obtainable in traditional experiments.
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Affiliation(s)
- Jong Yeon Lee
- Kavli Institute for Theoretical Physics, University of California, Santa Barbara, California 93106, USA
| | - Joshua Ramette
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Max A Metlitski
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Vladan Vuletić
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Wen Wei Ho
- Department of Physics, Stanford University, Stanford, California 94305, USA
- Department of Physics, National University of Singapore, Singapore 117542
- Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543
| | - Soonwon Choi
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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13
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Zhang WY, He MG, Sun H, Zheng YG, Liu Y, Luo A, Wang HY, Zhu ZH, Qiu PY, Shen YC, Wang XK, Lin W, Yu ST, Li BC, Xiao B, Li MD, Yang YM, Jiang X, Dai HN, Zhou Y, Ma X, Yuan ZS, Pan JW. Scalable Multipartite Entanglement Created by Spin Exchange in an Optical Lattice. PHYSICAL REVIEW LETTERS 2023; 131:073401. [PMID: 37656862 DOI: 10.1103/physrevlett.131.073401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 06/30/2023] [Indexed: 09/03/2023]
Abstract
Ultracold atoms in optical lattices form a competitive candidate for quantum computation owing to the excellent coherence properties, the highly parallel operations over spins, and the ultralow entropy achieved in qubit arrays. For this, a massive number of parallel entangled atom pairs have been realized in superlattices. However, the more formidable challenge is to scale up and detect multipartite entanglement, the basic resource for quantum computation, due to the lack of manipulations over local atomic spins in retroreflected bichromatic superlattices. In this Letter, we realize the functional building blocks in quantum-gate-based architecture by developing a cross-angle spin-dependent optical superlattice for implementing layers of quantum gates over moderately separated atoms incorporated with a quantum gas microscope for single-atom manipulation and detection. Bell states with a fidelity of 95.6(5)% and a lifetime of 2.20±0.13 s are prepared in parallel, and then connected to multipartite entangled states of one-dimensional ten-atom chains and two-dimensional plaquettes of 2×4 atoms. The multipartite entanglement is further verified with full bipartite nonseparability criteria. This offers a new platform toward scalable quantum computation and simulation.
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Affiliation(s)
- Wei-Yong Zhang
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, 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
| | - Ming-Gen He
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, 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
| | - Hui Sun
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, 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
| | - Yong-Guang Zheng
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, 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
| | - Ying Liu
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, 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
| | - An Luo
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, 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
| | - Han-Yi Wang
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, 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
| | - Zi-Hang Zhu
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, 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
| | - Pei-Yue Qiu
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, 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
| | - Ying-Chao Shen
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, 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
| | - Xuan-Kai Wang
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, 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
| | - Wan Lin
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, 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
| | - Song-Tao Yu
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, 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
| | - Bin-Chen Li
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, 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
| | - Bo Xiao
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, 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
| | - Meng-Da Li
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, 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
| | - Yu-Meng Yang
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, 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
| | - Xiao Jiang
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, 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
| | - Han-Ning Dai
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, 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
| | - You Zhou
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China
- Key Laboratory for Information Science of Electromagnetic Waves (Ministry of Education), Fudan University, Shanghai 200433, China
| | - Xiongfeng Ma
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
| | - Zhen-Sheng Yuan
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, 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, University of Science and Technology of China, Hefei 230088, China
| | - Jian-Wei Pan
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, 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, University of Science and Technology of China, Hefei 230088, China
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14
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Hines JA, Rajagopal SV, Moreau GL, Wahrman MD, Lewis NA, Marković O, Schleier-Smith M. Spin Squeezing by Rydberg Dressing in an Array of Atomic Ensembles. PHYSICAL REVIEW LETTERS 2023; 131:063401. [PMID: 37625064 DOI: 10.1103/physrevlett.131.063401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Revised: 06/08/2023] [Accepted: 06/20/2023] [Indexed: 08/27/2023]
Abstract
We report on the creation of an array of spin-squeezed ensembles of cesium atoms via Rydberg dressing, a technique that offers optical control over local interactions between neutral atoms. We optimize the coherence of the interactions by a stroboscopic dressing sequence that suppresses super-Poissonian loss. We thereby prepare squeezed states of N=200 atoms with a metrological squeezing parameter ξ^{2}=0.77(9) quantifying the reduction in phase variance below the standard quantum limit. We realize metrological gain across three spatially separated ensembles in parallel, with the strength of squeezing controlled by the local intensity of the dressing light. Our method can be applied to enhance the precision of tests of fundamental physics based on arrays of atomic clocks and to enable quantum-enhanced imaging of electromagnetic fields.
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Affiliation(s)
- Jacob A Hines
- Department of Physics, Stanford University, Stanford, California 94305, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | | | - Gabriel L Moreau
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - Michael D Wahrman
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - Neomi A Lewis
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - Ognjen Marković
- Department of Physics, Stanford University, Stanford, California 94305, USA
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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15
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Cao S, Wu B, Chen F, Gong M, Wu Y, Ye Y, Zha C, Qian H, Ying C, Guo S, Zhu Q, Huang HL, Zhao Y, Li S, Wang S, Yu J, Fan D, Wu D, Su H, Deng H, Rong H, Li Y, Zhang K, Chung TH, Liang F, Lin J, Xu Y, Sun L, Guo C, Li N, Huo YH, Peng CZ, Lu CY, Yuan X, Zhu X, Pan JW. Generation of genuine entanglement up to 51 superconducting qubits. Nature 2023:10.1038/s41586-023-06195-1. [PMID: 37438533 DOI: 10.1038/s41586-023-06195-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Accepted: 05/11/2023] [Indexed: 07/14/2023]
Abstract
Scalable generation of genuine multipartite entanglement with an increasing number of qubits is important for both fundamental interest and practical use in quantum-information technologies1,2. On the one hand, multipartite entanglement shows a strong contradiction between the prediction of quantum mechanics and local realization and can be used for the study of quantum-to-classical transition3,4. On the other hand, realizing large-scale entanglement is a benchmark for the quality and controllability of the quantum system and is essential for realizing universal quantum computing5-8. However, scalable generation of genuine multipartite entanglement on a state-of-the-art quantum device can be challenging, requiring accurate quantum gates and efficient verification protocols. Here we show a scalable approach for preparing and verifying intermediate-scale genuine entanglement on a 66-qubit superconducting quantum processor. We used high-fidelity parallel quantum gates and optimized the fidelitites of parallel single- and two-qubit gates to be 99.91% and 99.05%, respectively. With efficient randomized fidelity estimation9, we realized 51-qubit one-dimensional and 30-qubit two-dimensional cluster states and achieved fidelities of 0.637 ± 0.030 and 0.671 ± 0.006, respectively. On the basis of high-fidelity cluster states, we further show a proof-of-principle realization of measurement-based variational quantum eigensolver10 for perturbed planar codes. Our work provides a feasible approach for preparing and verifying entanglement with a few hundred qubits, enabling medium-scale quantum computing with superconducting quantum systems.
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Affiliation(s)
- Sirui Cao
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Bujiao Wu
- Center on Frontiers of Computing Studies, Peking University, Beijing, China
- School of Computer Science, Peking University, Beijing, China
| | - Fusheng Chen
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Ming Gong
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Yulin Wu
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Yangsen Ye
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Chen Zha
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Haoran Qian
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Chong Ying
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Shaojun Guo
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Qingling Zhu
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - He-Liang Huang
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Youwei Zhao
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Shaowei Li
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Shiyu Wang
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Jiale Yu
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Daojin Fan
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Dachao Wu
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Hong Su
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Hui Deng
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Hao Rong
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Yuan Li
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Kaili Zhang
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Tung-Hsun Chung
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Futian Liang
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Jin Lin
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Yu Xu
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Lihua Sun
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Cheng Guo
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Na Li
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Yong-Heng Huo
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Cheng-Zhi Peng
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Chao-Yang Lu
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Xiao Yuan
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China.
- Center on Frontiers of Computing Studies, Peking University, Beijing, China.
- School of Computer Science, Peking University, Beijing, China.
| | - Xiaobo Zhu
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China.
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China.
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China.
| | - Jian-Wei Pan
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, China.
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China.
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China.
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16
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Das A, Mahunta S, Agarwalla BK, Mukherjee V. Precision bound and optimal control in periodically modulated continuous quantum thermal machines. Phys Rev E 2023; 108:014137. [PMID: 37583225 DOI: 10.1103/physreve.108.014137] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 07/07/2023] [Indexed: 08/17/2023]
Abstract
We use Floquet formalism to study fluctuations in periodically modulated continuous quantum thermal machines. We present a generic theory for such machines, followed by specific examples of sinusoidal, optimal, and circular modulations, respectively. The thermodynamic uncertainty relations (TUR) hold for all modulations considered. Interestingly, in the case of sinusoidal modulation, the TUR ratio assumes a minimum at the heat engine to refrigerator transition point, while the chopped random basis optimization protocol allows us to keep the ratio small for a wide range of modulation frequencies. Furthermore, our numerical analysis suggests that TUR can show signatures of heat engine to refrigerator transition, for more generic modulation schemes. We also study bounds in fluctuations in the efficiencies of such machines; our results indicate that fluctuations in efficiencies are bounded from above for a refrigerator and from below for an engine. Overall, this study emphasizes the crucial role played by different modulation schemes in designing practical quantum thermal machines.
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Affiliation(s)
- Arpan Das
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziądzka 5/7, 87-100 Toruń, Poland
| | - Shishira Mahunta
- Department of Physical Sciences, Indian Institute of Science Education and Research Berhampur, Berhampur 760010, India
| | - Bijay Kumar Agarwalla
- Department of Physics, Indian Institute of Science Education and Research Pune, Pune 411008, India
| | - Victor Mukherjee
- Department of Physical Sciences, Indian Institute of Science Education and Research Berhampur, Berhampur 760010, India
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17
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Nie Z, Ning Z, Liu X, Zhang Y, Wang H, Cao E, Yan W. Creating multiple ultra-long longitudinal magnetization textures by strongly focusing azimuthally polarized circular Airy vortex beams. OPTICS EXPRESS 2023; 31:19089-19101. [PMID: 37381333 DOI: 10.1364/oe.490250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 05/10/2023] [Indexed: 06/30/2023]
Abstract
We come up with a simple feasible scheme for the creation of multiple ultra-long longitudinal magnetization textures. This is realized by directly strongly focusing azimuthally polarized circular Airy vortex beams onto an isotropic magneto-optical medium based on the vectorial diffraction theory and the inverse Faraday effect. It is found that, by jointly tuning the intrinsic parameters (i. e. the radius of main ring, the scaling factor, and the exponential decay factor) of the incoming Airy beams and the topological charges of the optical vortices, we are able to garner not only super-resolved scalable magnetization needles as usual, but also steerable magnetization oscillations and nested magnetization tubes with opposite polarities for the first time. These exotic magnetic behaviors depend on the extended interplay between the polarization singularity of multi-ring structured vectorial light fields and the additional vortex phase. The findings demonstrated are of great interest in opto-magnetism and emerging classical or quantum opto-magnetic applications.
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18
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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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19
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Torkzadeh-Tabrizi S, Faghihi MJ, Honarasa G. Phase space nonclassicality and sub-Poissonianity of deformed photon-added nonlinear cat states: algebraic and group theoretical approach. OPTICS LETTERS 2023; 48:688-691. [PMID: 36723564 DOI: 10.1364/ol.481568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 12/29/2022] [Indexed: 06/18/2023]
Abstract
In this Letter, we introduce four distinct classes of f-deformed photon-added nonlinear cat state. This would be achieved by recalling a nonlinear coherent states approach, as well as a particular class of Gilmore-Perelomov-type of SU(1,1) coherent state and a class of SU(2) coherent state. We then examine the role of photon addition and nonlinearity functions in the phase space structure and sub-Poissonianity of even, odd, and Yurke-Stoler nonlinear cat states. The effect of photon addition, which results in a π phase shift at the origin of the Wigner function toward negativity, interestingly enhances the nonclassicality by means of the Wigner function and Mandel parameter. Furthermore, owing to photon addition, we can observe a deformation in the Gaussian shape of the Wigner function, which may be found to be potentially useful in quantum noise reduction. Moreover, the deformation function shows a remarkable role in revealing the nonclassical behavior and can increase the depth and the domain of nonclassicality.
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20
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Information theoretical limits for quantum optimal control solutions: error scaling of noisy control channels. Sci Rep 2022; 12:21405. [PMID: 36496434 PMCID: PMC9741659 DOI: 10.1038/s41598-022-25770-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 12/05/2022] [Indexed: 12/13/2022] Open
Abstract
Accurate manipulations of an open quantum system require a deep knowledge of its controllability properties and the information content of the implemented control fields. By using tools of information and quantum optimal control theory, we provide analytical bounds (information-time bounds) to characterize our capability to control the system when subject to arbitrary sources of noise. Moreover, since the presence of an external noise field induces open quantum system dynamics, we also show that the results provided by the information-time bounds are in very good agreement with the Kofman-Kurizki universal formula describing decoherence processes. Finally, we numerically test the scaling of the control accuracy as a function of the noise parameters, by means of the dressed chopped random basis (dCRAB) algorithm for quantum optimal control.
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21
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Zhang C, Zhang WH, Sekatski P, Bancal JD, Zwerger M, Yin P, Li GC, Peng XX, Chen L, Han YJ, Xu JS, Huang YF, Chen G, Li CF, Guo GC. Certification of Genuine Multipartite Entanglement with General and Robust Device-Independent Witnesses. PHYSICAL REVIEW LETTERS 2022; 129:190503. [PMID: 36399745 DOI: 10.1103/physrevlett.129.190503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 09/28/2022] [Indexed: 06/16/2023]
Abstract
Genuine multipartite entanglement represents the strongest type of entanglement, which is an essential resource for quantum information processing. Standard methods to detect genuine multipartite entanglement, e.g., entanglement witnesses, state tomography, or quantum state verification, require full knowledge of the Hilbert space dimension and precise calibration of measurement devices, which are usually difficult to acquire in an experiment. The most radical way to overcome these problems is to detect entanglement solely based on the Bell-like correlations of measurement outcomes collected in the experiment, namely, device independently. However, it is difficult to certify genuine entanglement of practical multipartite states in this way, and even more difficult to quantify it, due to the difficulty in identifying optimal multipartite Bell inequalities and protocols tolerant to state impurity. In this Letter, we explore a general and robust device-independent method that can be applied to various realistic multipartite quantum states in arbitrary finite dimension, while merely relying on bipartite Bell inequalities. Our method allows us both to certify the presence of genuine multipartite entanglement and to quantify it. Several important classes of entangled states are tested with this method, leading to the detection of genuinely entangled states. We also certify genuine multipartite entanglement in weakly entangled Greenberger-Horne-Zeilinger states, showing that the method applies equally well to less standard states.
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Affiliation(s)
- Chao Zhang
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS 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
| | - Wen-Hao Zhang
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS 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
| | - Pavel Sekatski
- Department of Applied Physics, University of Geneva, Rue de l'École-de-Médecine, 1211 Geneva, Switzerland
| | - Jean-Daniel Bancal
- Université Paris-Saclay, CEA, CNRS, Institut de physique théorique, 91191 Gif-sur-Yvette, France
| | - Michael Zwerger
- Max Planck Institute for the Science of Light, Erlangen 91058, Germany
| | - Peng Yin
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS 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
| | - Gong-Chu Li
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS 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
| | - Xing-Xiang Peng
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS 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
| | - Lei Chen
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS 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
| | - Yong-Jian Han
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS 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
| | - Jin-Shi Xu
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS 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
| | - Yun-Feng Huang
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS 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
| | - Geng Chen
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS 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
| | - Chuan-Feng Li
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS 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
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS 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
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22
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Comparin T, Mezzacapo F, Roscilde T. Multipartite Entangled States in Dipolar Quantum Simulators. PHYSICAL REVIEW LETTERS 2022; 129:150503. [PMID: 36269956 DOI: 10.1103/physrevlett.129.150503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 09/14/2022] [Indexed: 06/16/2023]
Abstract
The scalable production of multipartite entangled states in ensembles of qubits is a crucial function of quantum devices, as such states are an essential resource both for fundamental studies on entanglement, as well as for applied tasks. Here we focus on the U(1) symmetric Hamiltonians for qubits with dipolar interactions-a model realized in several state-of-the-art quantum simulation platforms for lattice spin models, including Rydberg-atom arrays with resonant interactions. Making use of exact and variational simulations, we theoretically show that the nonequilibrium dynamics generated by this Hamiltonian shares fundamental features with that of the one-axis-twisting model, namely, the simplest interacting collective-spin model with U(1) symmetry. The evolution governed by the dipolar Hamiltonian generates a cascade of multipartite entangled states-spin-squeezed states, Schrödinger's cat states, and multicomponent superpositions of coherent spin states. Investigating systems with up to N=144 qubits, we observe full scalability of the entanglement features of these states directly related to metrology, namely, scalable spin squeezing at an evolution time O(N^{1/3}) and Heisenberg scaling of sensitivity of the spin parity to global rotations for cat states reached at times O(N). Our results suggest that the native Hamiltonian dynamics of state-of-the-art quantum simulation platforms, such as Rydberg-atom arrays, can act as a robust source of multipartite entanglement.
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Affiliation(s)
- Tommaso Comparin
- Université de Lyon, Ens de Lyon, CNRS, Laboratoire de Physique, F-69342 Lyon, France
| | - Fabio Mezzacapo
- Université de Lyon, Ens de Lyon, CNRS, Laboratoire de Physique, F-69342 Lyon, France
| | - Tommaso Roscilde
- Université de Lyon, Ens de Lyon, CNRS, Laboratoire de Physique, F-69342 Lyon, France
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23
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Yan ZZ, Spar BM, Prichard ML, Chi S, Wei HT, Ibarra-García-Padilla E, Hazzard KRA, Bakr WS. Two-Dimensional Programmable Tweezer Arrays of Fermions. PHYSICAL REVIEW LETTERS 2022; 129:123201. [PMID: 36179199 DOI: 10.1103/physrevlett.129.123201] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 06/27/2022] [Accepted: 07/29/2022] [Indexed: 06/16/2023]
Abstract
We prepare high-filling two-component arrays of tens of fermionic ^{6}Li atoms in optical tweezers, with the atoms in the ground motional state of each tweezer. Using a stroboscopic technique, we configure the arrays in various two-dimensional geometries with negligible Floquet heating. A full spin- and density-resolved readout of individual sites allows us to postselect near-zero entropy initial states for fermionic quantum simulation. We prepare a correlated state in a two-by-two tunnel-coupled Hubbard plaquette, demonstrating all the building blocks for realizing a programmable fermionic quantum simulator.
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Affiliation(s)
- Zoe Z Yan
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Benjamin M Spar
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Max L Prichard
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Sungjae Chi
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Hao-Tian Wei
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
- Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
| | - Eduardo Ibarra-García-Padilla
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
- Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
| | - Kaden R A Hazzard
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
- Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
| | - Waseem S Bakr
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
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24
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Katz O, Cetina M, Monroe C. N-Body Interactions between Trapped Ion Qubits via Spin-Dependent Squeezing. PHYSICAL REVIEW LETTERS 2022; 129:063603. [PMID: 36018637 DOI: 10.1103/physrevlett.129.063603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 07/05/2022] [Indexed: 06/15/2023]
Abstract
We describe a simple protocol for the single-step generation of N-body entangling interactions between trapped atomic ion qubits. We show that qubit state-dependent squeezing operations and displacement forces on the collective atomic motion can generate full N-body interactions. Similar to the Mølmer-Sørensen two-body Ising interaction at the core of most trapped ion quantum computers and simulators, the proposed operation is relatively insensitive to the state of motion. We show how this N-body gate operation allows for the single-step implementation of a family of N-bit gate operations such as the powerful N-Toffoli gate, which flips a single qubit if and only if all other N-1 qubits are in a particular state.
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Affiliation(s)
- Or Katz
- Duke Quantum Center, Duke University, Durham, North Carolina 27701, USA
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
| | - Marko Cetina
- Duke Quantum Center, Duke University, Durham, North Carolina 27701, USA
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
| | - Christopher Monroe
- Duke Quantum Center, Duke University, Durham, North Carolina 27701, USA
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
- IonQ, Inc., College Park, Maryland 20740, USA
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25
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Trisnadi J, Zhang M, Weiss L, Chin C. Design and construction of a quantum matter synthesizer. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:083203. [PMID: 36050064 DOI: 10.1063/5.0100088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 07/23/2022] [Indexed: 06/15/2023]
Abstract
The quantum matter synthesizer (QMS) is a new quantum simulation platform in which individual particles in a lattice can be resolved and re-arranged into arbitrary patterns. The ability to spatially manipulate ultracold atoms and control their tunneling and interactions at the single-particle level allows full control of a many-body quantum system. We present the design and characterization of the QMS, which integrates into a single ultra-stable apparatus a two-dimensional optical lattice, a moving optical tweezer array formed by a digital micromirror device, and site-resolved atomic imaging. We demonstrate excellent mechanical stability between the lattice and tweezer array with relative fluctuations below 10 nm, diffraction-limited imaging at a resolution of 655 nm, and high-speed real-time control of the tweezer array at a 2.52 kHz refresh rate, which will be adopted to realize fast rearrangement of atoms. The QMS also features new technologies and schemes, such as nanotextured anti-reflective windows and all-optical long-distance transport of atoms.
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Affiliation(s)
- Jonathan Trisnadi
- James Franck Institute, Enrico Fermi Institute, and Department of Physics, The University of Chicago, Chicago, Illinois 60637, USA
| | - Mingjiamei Zhang
- James Franck Institute, Enrico Fermi Institute, and Department of Physics, The University of Chicago, Chicago, Illinois 60637, USA
| | - Lauren Weiss
- James Franck Institute, Enrico Fermi Institute, and Department of Physics, The University of Chicago, Chicago, Illinois 60637, USA
| | - Cheng Chin
- James Franck Institute, Enrico Fermi Institute, and Department of Physics, The University of Chicago, Chicago, Illinois 60637, USA
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26
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Efficient generation of entangled multiphoton graph states from a single atom. Nature 2022; 608:677-681. [PMID: 36002484 PMCID: PMC9402438 DOI: 10.1038/s41586-022-04987-5] [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: 01/26/2022] [Accepted: 06/16/2022] [Indexed: 11/23/2022]
Abstract
The central technological appeal of quantum science resides in exploiting quantum effects, such as entanglement, for a variety of applications, including computing, communication and sensing1. The overarching challenge in these fields is to address, control and protect systems of many qubits against decoherence2. Against this backdrop, optical photons, naturally robust and easy to manipulate, represent ideal qubit carriers. However, the most successful technique so far for creating photonic entanglement3 is inherently probabilistic and, therefore, subject to severe scalability limitations. Here we report the implementation of a deterministic protocol4–6 for the creation of photonic entanglement with a single memory atom in a cavity7. We interleave controlled single-photon emissions with tailored atomic qubit rotations to efficiently grow Greenberger–Horne–Zeilinger (GHZ) states8 of up to 14 photons and linear cluster states9 of up to 12 photons with a fidelity lower bounded by 76(6)% and 56(4)%, respectively. Thanks to a source-to-detection efficiency of 43.18(7)% per photon, we measure these large states about once every minute, which is orders of magnitude faster than in any previous experiment3,10–13. In the future, this rate could be increased even further, the scheme could be extended to two atoms in a cavity14,15 or several sources could be quantum mechanically coupled16, to generate higher-dimensional cluster states17. Overcoming the limitations encountered by probabilistic schemes for photonic entanglement generation, our results may offer a way towards scalable measurement-based quantum computation18,19 and communication20,21. Using a single memory atom in a cavity, a deterministic protocol is implemented to efficiently grow Greenberger–Horne–Zeilinger and linear cluster states by means of single-photon emissions.
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27
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Sauvage F, Mintert F. Optimal Control of Families of Quantum Gates. PHYSICAL REVIEW LETTERS 2022; 129:050507. [PMID: 35960583 DOI: 10.1103/physrevlett.129.050507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 06/27/2022] [Indexed: 06/15/2023]
Abstract
Quantum optimal control (QOC) enables the realization of accurate operations, such as quantum gates, and supports the development of quantum technologies. To date, many QOC frameworks have been developed, but those remain only naturally suited to optimize a single targeted operation at a time. We extend this concept to optimal control with a continuous family of targets, and demonstrate that an optimization based on neural networks can find families of time-dependent Hamiltonians realizing desired classes of quantum gates in minimal time.
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Affiliation(s)
- Frédéric Sauvage
- Physics Department, Blackett Laboratory, Imperial College London, Prince Consort Road, SW7 2BW, United Kingdom
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Florian Mintert
- Physics Department, Blackett Laboratory, Imperial College London, Prince Consort Road, SW7 2BW, United Kingdom
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28
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Li B, Qin W, Jiao YF, Zhai CL, Xu XW, Kuang LM, Jing H. Optomechanical Schrödinger cat states in a cavity Bose-Einstein condensate. FUNDAMENTAL RESEARCH 2022. [DOI: 10.1016/j.fmre.2022.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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29
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Celik OT, Sarabalis CJ, Mayor FM, Stokowski HS, Herrmann JF, McKenna TP, Lee NRA, Jiang W, Multani KKS, Safavi-Naeini AH. High-bandwidth CMOS-voltage-level electro-optic modulation of 780 nm light in thin-film lithium niobate. OPTICS EXPRESS 2022; 30:23177-23186. [PMID: 36225003 DOI: 10.1364/oe.460119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 05/30/2022] [Indexed: 06/16/2023]
Abstract
Integrated photonics operating at visible-near-infrared (VNIR) wavelengths offer scalable platforms for advancing optical systems for addressing atomic clocks, sensors, and quantum computers. The complexity of free-space control optics causes limited addressability of atoms and ions, and this remains an impediment on scalability and cost. Networks of Mach-Zehnder interferometers can overcome challenges in addressing atoms by providing high-bandwidth electro-optic control of multiple output beams. Here, we demonstrate a VNIR Mach-Zehnder interferometer on lithium niobate on sapphire with a CMOS voltage-level compatible full-swing voltage of 4.2 V and an electro-optic bandwidth of 2.7 GHz occupying only 0.35 mm2. Our waveguides exhibit 1.6 dB/cm propagation loss and our microring resonators have intrinsic quality factors of 4.4 × 105. This specialized platform for VNIR integrated photonics can open new avenues for addressing large arrays of qubits with high precision and negligible cross-talk.
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30
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Experimental Realization of Reconfigurable Photonic Lattices in Coherent Rydberg Atomic Vapors. PHOTONICS 2022. [DOI: 10.3390/photonics9060422] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We experimentally demonstrated the formation of a one-dimensional electromagnetically induced optical lattice in coherently prepared three-level 85Rb Rydberg atomic vapors with electromagnetically induced transparency (EIT). The one-dimensional photonic lattice was optically induced by a coupling field with a spatially periodical intensity distribution deriving from the interference of two strong Gaussian beams from the same laser source (~480 nm). Under the Rydberg-EIT condition, the incident weak probe beam can feel a tunable spatially modulated susceptibility, which is verified by the controllable discrete diffraction pattern observed at the output plane of the vapor cell. This investigation not only opens the door for experimentally introducing the strong interaction between Rydberg atoms to govern the beam dynamics in photonic lattices based on atomic coherence but also provides an easily accessible periodic environment for exploring Rydberg-atom physics and related applications.
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31
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Müller MM, Said RS, Jelezko F, Calarco T, Montangero S. One decade of quantum optimal control in the chopped random basis. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2022; 85:076001. [PMID: 35605567 DOI: 10.1088/1361-6633/ac723c] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 05/23/2022] [Indexed: 06/15/2023]
Abstract
The chopped random basis (CRAB) ansatz for quantum optimal control has been proven to be a versatile tool to enable quantum technology applications such as quantum computing, quantum simulation, quantum sensing, and quantum communication. Its capability to encompass experimental constraints-while maintaining an access to the usually trap-free control landscape-and to switch from open-loop to closed-loop optimization (including with remote access-or RedCRAB) is contributing to the development of quantum technology on many different physical platforms. In this review article we present the development, the theoretical basis and the toolbox for this optimization algorithm, as well as an overview of the broad range of different theoretical and experimental applications that exploit this powerful technique.
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Affiliation(s)
- Matthias M Müller
- Peter Grünberg Institute-Quantum Control (PGI-8), Forschungszentrum Jülich GmbH, D-52425 Germany
| | - Ressa S Said
- Institute for Quantum Optics & Center for Integrated Quantum Science and Technology, Universität Ulm, D-89081 Germany
| | - Fedor Jelezko
- Institute for Quantum Optics & Center for Integrated Quantum Science and Technology, Universität Ulm, D-89081 Germany
| | - Tommaso Calarco
- Peter Grünberg Institute-Quantum Control (PGI-8), Forschungszentrum Jülich GmbH, D-52425 Germany
- Institute for Theoretical Physics, University of Cologne, D-50937 Germany
| | - Simone Montangero
- Dipartimento di Fisica e Astronomia 'G. Galilei', Università degli Studi di Padova & INFN, Sezione di Padova, I-35131 Italy
- Padua Quantum Technology Center, Università degli Studi di Padova, I-35131 Italy
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32
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Schleier-Smith M. Solving a puzzle with atomic qubits. Science 2022; 376:1155-1156. [PMID: 35679424 DOI: 10.1126/science.abq3754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
A quantum com puter makes light work of the maximum independent set problem.
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33
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Multi-qubit entanglement and algorithms on a neutral-atom quantum computer. Nature 2022; 604:457-462. [PMID: 35444321 DOI: 10.1038/s41586-022-04603-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Accepted: 03/02/2022] [Indexed: 11/08/2022]
Abstract
Gate-model quantum computers promise to solve currently intractable computational problems if they can be operated at scale with long coherence times and high-fidelity logic. Neutral-atom hyperfine qubits provide inherent scalability owing to their identical characteristics, long coherence times and ability to be trapped in dense, multidimensional arrays1. Combined with the strong entangling interactions provided by Rydberg states2-4, all the necessary characteristics for quantum computation are available. Here we demonstrate several quantum algorithms on a programmable gate-model neutral-atom quantum computer in an architecture based on individual addressing of single atoms with tightly focused optical beams scanned across a two-dimensional array of qubits. Preparation of entangled Greenberger-Horne-Zeilinger (GHZ) states5 with up to six qubits, quantum phase estimation for a chemistry problem6 and the quantum approximate optimization algorithm (QAOA)7 for the maximum cut (MaxCut) graph problem are demonstrated. These results highlight the emergent capability of neutral-atom qubit arrays for universal, programmable quantum computation, as well as preparation of non-classical states of use for quantum-enhanced sensing.
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34
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Versatile neutral atoms take on quantum circuits. Nature 2022; 604:429-430. [PMID: 35444314 DOI: 10.1038/d41586-022-01029-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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35
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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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36
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Jansen ND, Loucks M, Gilbert S, Fleming-Dittenber C, Egbert J, Hunt KLC. Shannon and von Neumann entropies of multi-qubit Schrödinger's cat states. Phys Chem Chem Phys 2022; 24:7666-7681. [PMID: 35297927 DOI: 10.1039/d1cp05255a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Using IBM's publicly accessible quantum computers, we have analyzed the entropies of Schrödinger's cat states, which have the form Ψ = (1/2)1/2 [|0 0 0⋯0〉 + |1 1 1⋯1〉]. We have obtained the average Shannon entropy SSo of the distribution over measurement outcomes from 75 runs of 8192 shots, for each of the numbers of entangled qubits, on each of the quantum computers tested. For the distribution over N fault-free measurements on pure cat states, SSo would approach one as N → ∞, independent of the number of qubits; but we have found that SSo varies nearly linearly with the number of qubits n. The slope of SSoversus the number of qubits differs among computers with the same quantum volumes. We have developed a two-parameter model that reproduces the near-linear dependence of the entropy on the number of qubits, based on the probabilities of observing the output 0 when a qubit is set to |0〉 and 1 when it is set to |1〉. The slope increases as the error rate increases. The slope provides a sensitive measure of the accuracy of a quantum computer, so it serves as a quickly determinable index of performance. We have used tomographic methods with error mitigation as described in the qiskit documentation to find the density matrix ρ and evaluate the von Neumann entropies of the cat states. From the reduced density matrices for individual qubits, we have calculated the entanglement entropies. The reduced density matrices represent mixed states with approximately 50/50 probabilities for states |0〉 and |1〉. The entanglement entropies are very close to one.
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Affiliation(s)
- Nathan D Jansen
- Department of Chemistry, Michigan State University, East Lansing, Michigan, 48824, USA.
| | - Matthew Loucks
- Department of Chemistry, Michigan State University, East Lansing, Michigan, 48824, USA.
| | - Scott Gilbert
- Department of Chemistry, Michigan State University, East Lansing, Michigan, 48824, USA.
| | | | - Julia Egbert
- Department of Chemistry, Michigan State University, East Lansing, Michigan, 48824, USA.
| | - Katharine L C Hunt
- Department of Chemistry, Michigan State University, East Lansing, Michigan, 48824, USA.
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37
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Marciniak CD, Feldker T, Pogorelov I, Kaubruegger R, Vasilyev DV, van Bijnen R, Schindler P, Zoller P, Blatt R, Monz T. Optimal metrology with programmable quantum sensors. Nature 2022; 603:604-609. [PMID: 35322252 DOI: 10.1038/s41586-022-04435-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 01/18/2022] [Indexed: 11/09/2022]
Abstract
Quantum sensors are an established technology that has created new opportunities for precision sensing across the breadth of science. Using entanglement for quantum enhancement will allow us to construct the next generation of sensors that can approach the fundamental limits of precision allowed by quantum physics. However, determining how state-of-the-art sensing platforms may be used to converge to these ultimate limits is an outstanding challenge. Here we merge concepts from the field of quantum information processing with metrology, and successfully implement experimentally a programmable quantum sensor operating close to the fundamental limits imposed by the laws of quantum mechanics. We achieve this by using low-depth, parametrized quantum circuits implementing optimal input states and measurement operators for a sensing task on a trapped-ion experiment. With 26 ions, we approach the fundamental sensing limit up to a factor of 1.45 ± 0.01, outperforming conventional spin-squeezing with a factor of 1.87 ± 0.03. Our approach reduces the number of averages to reach a given Allan deviation by a factor of 1.59 ± 0.06 compared with traditional methods not using entanglement-enabled protocols. We further perform on-device quantum-classical feedback optimization to 'self-calibrate' the programmable quantum sensor with comparable performance. This ability illustrates that this next generation of quantum sensor can be used without previous knowledge of the device or its noise environment.
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Affiliation(s)
| | | | | | - Raphael Kaubruegger
- Institute for Quantum Optics and Quantum Information, Innsbruck, Austria.,Center for Quantum Physics, Innsbruck, Austria
| | - Denis V Vasilyev
- Institute for Quantum Optics and Quantum Information, Innsbruck, Austria.,Center for Quantum Physics, Innsbruck, Austria
| | - Rick van Bijnen
- Institute for Quantum Optics and Quantum Information, Innsbruck, Austria.,Center for Quantum Physics, Innsbruck, Austria
| | | | - Peter Zoller
- Institute for Quantum Optics and Quantum Information, Innsbruck, Austria.,Center for Quantum Physics, Innsbruck, Austria
| | - Rainer Blatt
- Institut für Experimentalphysik, Innsbruck, Austria.,Institute for Quantum Optics and Quantum Information, Innsbruck, Austria
| | - Thomas Monz
- Institut für Experimentalphysik, Innsbruck, Austria. .,Alpine Quantum Technologies, Innsbruck, Austria.
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38
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Guo Y, Zhang H, Guo X, Zhang Y, Zhang T. High-order continuous-variable coherence of phase-dependent squeezed state. OPTICS EXPRESS 2022; 30:8461-8473. [PMID: 35299298 DOI: 10.1364/oe.450204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 02/21/2022] [Indexed: 06/14/2023]
Abstract
We study continuous variable coherence of phase-dependent squeezed state based on an extended Hanbury Brown-Twiss scheme. High-order coherence is continuously varied by adjusting squeezing parameter r, displacement α, and squeezing phase θ. We also analyze effects of background noise γ and detection efficiency η on the measurements. As the squeezing phase shifts from 0 to π, the photon statistics of the squeezed state continuously change from the anti-bunching (g(n) < 1) to super-bunching (g(n) > n!) which shows a transition from particle nature to wave nature. The experiment feasibility is also examined. It provides a practical method to generate phase-dependent squeezed states with high-order continuous-variable coherence by tuning squeezing phase θ. The controllable coherence source can be applied to sensitivity improvement in gravitational wave detection and quantum imaging.
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39
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Zhang S, Wu YK, Li C, Jiang N, Pu YF, Duan LM. Quantum-Memory-Enhanced Preparation of Nonlocal Graph States. PHYSICAL REVIEW LETTERS 2022; 128:080501. [PMID: 35275664 DOI: 10.1103/physrevlett.128.080501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Accepted: 01/27/2022] [Indexed: 06/14/2023]
Abstract
Graph states are an important class of multipartite entangled states. Previous experimental generation of graph states and in particular the Greenberger-Horne-Zeilinger (GHZ) states in linear optics quantum information schemes is subjected to an exponential decay in efficiency versus the system size, which limits its large-scale applications in quantum networks. Here, we demonstrate an efficient scheme to prepare graph states with only a polynomial overhead using long-lived atomic quantum memories. We generate atom-photon entangled states in two atomic ensembles asynchronously, retrieve the stored atomic excitations only when both sides succeed, and further project them into a four-photon GHZ state. We measure the fidelity of this GHZ state and further demonstrate its applications in the violation of Bell-type inequalities and in quantum cryptography. Our work demonstrates the prospect of efficient generation of multipartite entangled states in large-scale distributed systems with applications in quantum information processing and metrology.
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Affiliation(s)
- Sheng Zhang
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, People's Republic of China
| | - Yu-Kai Wu
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, People's Republic of China
| | - Chang Li
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, People's Republic of China
| | - Nan Jiang
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, People's Republic of China
| | - Yun-Fei Pu
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, People's Republic of China
| | - Lu-Ming Duan
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, People's Republic of China
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40
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Wilson JT, Saskin S, Meng Y, Ma S, Dilip R, Burgers AP, Thompson JD. Trapping Alkaline Earth Rydberg Atoms Optical Tweezer Arrays. PHYSICAL REVIEW LETTERS 2022; 128:033201. [PMID: 35119888 DOI: 10.1103/physrevlett.128.033201] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 11/16/2021] [Accepted: 01/03/2022] [Indexed: 06/14/2023]
Abstract
Neutral atom qubits with Rydberg-mediated interactions are a leading platform for developing large-scale coherent quantum systems. In the majority of experiments to date, the Rydberg states are not trapped by the same potential that confines ground state atoms, resulting in atom loss and constraints on the achievable interaction time. In this Letter, we demonstrate that the Rydberg states of an alkaline earth atom, ytterbium, can be stably trapped by the same red-detuned optical tweezer that also confines the ground state, by leveraging the polarizability of the Yb^{+} ion core. Using the previously unobserved ^{3}S_{1} series, we demonstrate trapped Rydberg atom lifetimes exceeding 100 μs, and observe no evidence of auto- or photoionization from the trap light for these states. We measure a coherence time of T_{2}=59 μs between two Rydberg levels, exceeding the 28 μs lifetime of untrapped Rydberg atoms under the same conditions. These results are promising for extending the interaction time of Rydberg atom arrays for quantum simulation and computing, and are vital to capitalize on the extended Rydberg lifetimes in circular states or cryogenic environments.
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Affiliation(s)
- J T Wilson
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08540, USA
| | - S Saskin
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08540, USA
- Department of Physics, Princeton University, Princeton, New Jersey 08540, USA
| | - Y Meng
- Vienna Center for Quantum Science and Technology, TU Wien, Atominstitut, Stadionallee 2, 1020 Vienna, Austria
| | - S Ma
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08540, USA
- Department of Physics, Princeton University, Princeton, New Jersey 08540, USA
| | - R Dilip
- Department of Physics, Princeton University, Princeton, New Jersey 08540, USA
| | - A P Burgers
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08540, USA
| | - J D Thompson
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08540, USA
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41
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Liu F, Yang ZC, Bienias P, Iadecola T, Gorshkov AV. Localization and Criticality in Antiblockaded Two-Dimensional Rydberg Atom Arrays. PHYSICAL REVIEW LETTERS 2022; 128:013603. [PMID: 35061449 DOI: 10.1103/physrevlett.128.013603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 10/30/2021] [Accepted: 12/13/2021] [Indexed: 06/14/2023]
Abstract
Controllable Rydberg atom arrays have provided new insights into fundamental properties of quantum matter both in and out of equilibrium. In this work, we study the effect of experimentally relevant positional disorder on Rydberg atoms trapped in a 2D square lattice under antiblockade (facilitation) conditions. We show that the facilitation conditions lead the connectivity graph of a particular subspace of the full Hilbert space to form a 2D Lieb lattice, which features a singular flat band. Remarkably, we find three distinct regimes as the disorder strength is varied: a critical regime, a delocalized but nonergodic regime, and a regime with a disorder-induced flat band. The critical regime's existence depends crucially upon the singular flat band in our model, and is absent in any 1D array or ladder system. We propose to use quench dynamics to probe the three different regimes experimentally.
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Affiliation(s)
- Fangli Liu
- Joint Quantum Institute and Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, Maryland 20742, USA
| | - Zhi-Cheng Yang
- Joint Quantum Institute and Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, Maryland 20742, USA
| | - Przemyslaw Bienias
- Joint Quantum Institute and Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, Maryland 20742, USA
| | - Thomas Iadecola
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - Alexey V Gorshkov
- Joint Quantum Institute and Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, Maryland 20742, USA
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42
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Rath A, Branciard C, Minguzzi A, Vermersch B. Quantum Fisher Information from Randomized Measurements. PHYSICAL REVIEW LETTERS 2021; 127:260501. [PMID: 35029488 DOI: 10.1103/physrevlett.127.260501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 11/17/2021] [Indexed: 06/14/2023]
Abstract
The quantum Fisher information (QFI) is a fundamental quantity of interest in many areas from quantum metrology to quantum information theory. It can in particular be used as a witness to establish the degree of multiparticle entanglement in quantum many-body systems. In this work, we use polynomials of the density matrix to construct monotonically increasing lower bounds that converge to the QFI. Using randomized measurements we propose a protocol to accurately estimate these lower bounds in state-of-the-art quantum technological platforms. We estimate the number of measurements needed to achieve a given accuracy and confidence level in the bounds, and present two examples of applications of the method in quantum systems made of coupled qubits and collective spins.
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Affiliation(s)
- Aniket Rath
- Université Grenoble Alpes, CNRS, LPMMC, 38000 Grenoble, France
| | - Cyril Branciard
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France
| | - Anna Minguzzi
- Université Grenoble Alpes, CNRS, LPMMC, 38000 Grenoble, France
| | - Benoît Vermersch
- Université Grenoble Alpes, CNRS, LPMMC, 38000 Grenoble, France
- Center for Quantum Physics, University of Innsbruck, Innsbruck A-6020, Austria
- Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, Innsbruck A-6020, Austria
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43
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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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44
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Programmable interactions and emergent geometry in an array of atom clouds. Nature 2021; 600:630-635. [PMID: 34937894 DOI: 10.1038/s41586-021-04156-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 10/15/2021] [Indexed: 11/08/2022]
Abstract
Interactions govern the flow of information and the formation of correlations between constituents of many-body quantum systems, dictating phases of matter found in nature and forms of entanglement generated in the laboratory. Typical interactions decay with distance and thus produce a network of connectivity governed by geometry-such as the crystalline structure of a material or the trapping sites of atoms in a quantum simulator1,2. However, many envisioned applications in quantum simulation and computation require more complex coupling graphs including non-local interactions, which feature in models of information scrambling in black holes3-6 and mappings of hard optimization problems onto frustrated classical magnets7-11. Here we describe the realization of programmable non-local interactions in an array of atomic ensembles within an optical cavity, in which photons carry information between atomic spins12-19. By programming the distance dependence of the interactions, we access effective geometries for which the dimensionality, topology and metric are entirely distinct from the physical geometry of the array. As examples, we engineer an antiferromagnetic triangular ladder, a Möbius strip with sign-changing interactions and a treelike geometry inspired by concepts of quantum gravity5,20-22. The tree graph constitutes a toy model of holographic duality21,22, in which the quantum system lies on the boundary of a higher-dimensional geometry that emerges from measured correlations23. Our work provides broader prospects for simulating frustrated magnets and topological phases24, investigating quantum optimization paradigms10,11,25,26 and engineering entangled resource states for sensing and computation27,28.
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45
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Mukherjee V, Divakaran U. Many-body quantum thermal machines. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:454001. [PMID: 34359061 DOI: 10.1088/1361-648x/ac1b60] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 08/06/2021] [Indexed: 06/13/2023]
Abstract
Thermodynamics of quantum systems and quantum thermal machines are rapidly developing fields, which have already delivered several promising results, as well as raised many intriguing questions. Many-body quantum machines present new opportunities stemming from many-body effects. At the same time, they pose new challenges related to many-body physics. In this short review we discuss some of the recent developments on technologies based on many-body quantum systems. We mainly focus on many-body effects in quantum thermal machines. We also briefly address the role played by many-body systems in the development of quantum batteries and quantum probes.
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Affiliation(s)
- Victor Mukherjee
- Department of Physical Sciences, IISER Berhampur, Berhampur 760010, India
| | - Uma Divakaran
- Department of Physics, Indian Institute of Technology Palakkad, Palakkad, 678557, India
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46
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Maskara N, Michailidis AA, Ho WW, Bluvstein D, Choi S, Lukin MD, Serbyn M. Discrete Time-Crystalline Order Enabled by Quantum Many-Body Scars: Entanglement Steering via Periodic Driving. PHYSICAL REVIEW LETTERS 2021; 127:090602. [PMID: 34506175 DOI: 10.1103/physrevlett.127.090602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 05/26/2021] [Indexed: 06/13/2023]
Abstract
The control of many-body quantum dynamics in complex systems is a key challenge in the quest to reliably produce and manipulate large-scale quantum entangled states. Recently, quench experiments in Rydberg atom arrays [Bluvstein et al. Science 371, 1355 (2021)SCIEAS0036-807510.1126/science.abg2530] demonstrated that coherent revivals associated with quantum many-body scars can be stabilized by periodic driving, generating stable subharmonic responses over a wide parameter regime. We analyze a simple, related model where these phenomena originate from spatiotemporal ordering in an effective Floquet unitary, corresponding to discrete time-crystalline behavior in a prethermal regime. Unlike conventional discrete time crystals, the subharmonic response exists only for Néel-like initial states, associated with quantum scars. We predict robustness to perturbations and identify emergent timescales that could be observed in future experiments. Our results suggest a route to controlling entanglement in interacting quantum systems by combining periodic driving with many-body scars.
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Affiliation(s)
- N Maskara
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | | | - W W Ho
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - D Bluvstein
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - S Choi
- Department of Physics, University of California Berkeley, Berkeley, California 94720, USA
- Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - M D Lukin
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - M Serbyn
- IST Austria, Am Campus 1, 3400 Klosterneuburg, Austria
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47
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Qin W, Miranowicz A, Jing H, Nori F. Generating Long-Lived Macroscopically Distinct Superposition States in Atomic Ensembles. PHYSICAL REVIEW LETTERS 2021; 127:093602. [PMID: 34506157 DOI: 10.1103/physrevlett.127.093602] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 05/11/2021] [Accepted: 07/02/2021] [Indexed: 06/13/2023]
Abstract
We propose to create and stabilize long-lived macroscopic quantum superposition states in atomic ensembles. We show that using a fully quantum parametric amplifier can cause the simultaneous decay of two atoms and, in turn, create stabilized atomic Schrödinger cat states. Remarkably, even with modest parameters these intracavity atomic cat states can have an extremely long lifetime, up to 4 orders of magnitude longer than that of intracavity photonic cat states under the same parameter conditions, reaching tens of milliseconds. This lifetime of atomic cat states is ultimately limited to several seconds by extremely weak spin relaxation and thermal noise. Our work opens up a new way toward the long-standing goal of generating large-size and long-lived cat states, with immediate interests both in fundamental studies and noise-immune quantum technologies.
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Affiliation(s)
- Wei Qin
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
| | - 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
| | - Hui Jing
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
- Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, Department of Physics and Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, Changsha 410081, China
| | - Franco Nori
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
- Department of Physics, The University of Michigan, Ann Arbor, Michigan 48109, USA
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48
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Xu W, Venkatramani AV, Cantú SH, Šumarac T, Klüsener V, Lukin MD, Vuletić V. Fast Preparation and Detection of a Rydberg Qubit Using Atomic Ensembles. PHYSICAL REVIEW LETTERS 2021; 127:050501. [PMID: 34397223 DOI: 10.1103/physrevlett.127.050501] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 05/15/2021] [Accepted: 06/29/2021] [Indexed: 06/13/2023]
Abstract
We demonstrate a new approach for fast preparation, manipulation, and collective readout of an atomic Rydberg-state qubit. By making use of Rydberg blockade inside a small atomic ensemble, we prepare a single qubit within 3 μs with a success probability of F_{p}=0.93±0.02, rotate it, and read out its state in 6 μs with a single-shot fidelity of F_{d}=0.92±0.04. The ensemble-assisted detection is 10^{3} times faster than imaging of a single atom with the same optical resolution, and enables fast repeated nondestructive measurement. We observe qubit coherence times of 15 μs, much longer than the π rotation time of 90 ns. Potential applications ranging from faster quantum information processing in atom arrays to efficient implementation of quantum error correction are discussed.
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Affiliation(s)
- Wenchao Xu
- Department of Physics and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Aditya V Venkatramani
- Department of Physics and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Sergio H Cantú
- Department of Physics and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Tamara Šumarac
- Department of Physics and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Valentin Klüsener
- Department of Physics and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- University of Erlangen-Nuremberg, Erlangen 91054, Germany
| | - Mikhail D Lukin
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Vladan Vuletić
- Department of Physics and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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49
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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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50
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Quantum phases of matter on a 256-atom programmable quantum simulator. Nature 2021; 595:227-232. [PMID: 34234334 DOI: 10.1038/s41586-021-03582-4] [Citation(s) in RCA: 113] [Impact Index Per Article: 37.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 04/26/2021] [Indexed: 11/09/2022]
Abstract
Motivated by far-reaching applications ranging from quantum simulations of complex processes in physics and chemistry to quantum information processing1, a broad effort is currently underway to build large-scale programmable quantum systems. Such systems provide insights into strongly correlated quantum matter2-6, while at the same time enabling new methods for computation7-10 and metrology11. Here we demonstrate a programmable quantum simulator based on deterministically prepared two-dimensional arrays of neutral atoms, featuring strong interactions controlled by coherent atomic excitation into Rydberg states12. Using this approach, we realize a quantum spin model with tunable interactions for system sizes ranging from 64 to 256 qubits. We benchmark the system by characterizing high-fidelity antiferromagnetically ordered states and demonstrating quantum critical dynamics consistent with an Ising quantum phase transition in (2 + 1) dimensions13. We then create and study several new quantum phases that arise from the interplay between interactions and coherent laser excitation14, experimentally map the phase diagram and investigate the role of quantum fluctuations. Offering a new lens into the study of complex quantum matter, these observations pave the way for investigations of exotic quantum phases, non-equilibrium entanglement dynamics and hardware-efficient realization of quantum algorithms.
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