51
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Pachniak E, Malinovskaya SA. Creation of quantum entangled states of Rydberg atoms via chirped adiabatic passage. Sci Rep 2021; 11:12980. [PMID: 34155254 PMCID: PMC8217571 DOI: 10.1038/s41598-021-92325-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 06/07/2021] [Indexed: 11/28/2022] Open
Abstract
Entangled states are crucial for modern quantum enabled technology which makes their creation key for future developments. In this paper, a robust quantum control methodology is presented to create entangled states of two typical classes, the W and the Greenberger–Horne–Zeilinger (GHZ). It was developed from the analysis of a chain of alkali atoms \documentclass[12pt]{minimal}
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\begin{document}$$^{87}Rb$$\end{document}87Rb interaction with laser pulses, which leads to the two-photon transitions from the ground to the Rydberg states with a predetermined magnetic quantum number. The methodology is based on the mechanism of the two-photon excitation, adiabatic for the GHZ and non-adiabatic for the W state, induced by the overlapping chirped pulses and governed by the Rabi frequency, the one-photon detuning, and the strength of the Rydberg–Rydberg interactions.
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Affiliation(s)
- Elliot Pachniak
- Department of Physics, Stevens Institute of Technology, Hoboken, NJ, 07030, USA
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52
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53
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Shumilin AV, Smirnov DS. Nuclear Spin Dynamics, Noise, Squeezing, and Entanglement in Box Model. PHYSICAL REVIEW LETTERS 2021; 126:216804. [PMID: 34114866 DOI: 10.1103/physrevlett.126.216804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 03/24/2021] [Accepted: 04/27/2021] [Indexed: 06/12/2023]
Abstract
We obtain a compact analytical solution for the nonlinear equation for the nuclear spin dynamics in the central spin box model in the limit of many nuclear spins. The total nuclear spin component along the external magnetic field is conserved and the two perpendicular components precess or oscillate depending on the electron spin polarization, with the frequency, determined by the nuclear spin polarization. As applications of our solution, we calculate the nuclear spin noise spectrum and describe the effects of nuclear spin squeezing and many body entanglement in the absence of a system excitation.
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Affiliation(s)
| | - D S Smirnov
- Ioffe Institute, 194021 St. Petersburg, Russia
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54
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Yin HD, Shao XQ. Gaussian soft control-based quantum fan-out gate in ground-state manifolds of neutral atoms. OPTICS LETTERS 2021; 46:2541-2544. [PMID: 33988630 DOI: 10.1364/ol.424469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 04/28/2021] [Indexed: 06/12/2023]
Abstract
We propose a reliable scheme for one-step synthesizing of a quantum fan-out gate in a system of neutral atoms. By introducing the off-resonant driving fields with Gaussian temporal modulation, the dynamics of the system is strictly restricted to the ground-state subspace on the basis of unconventional Rydberg pumping, which exhibits more robustness than the constant driving method against the fluctuation of system parameters, such as operating time and environment noise. As a direct application of this quantum fan-out gate, we discuss in detail the preparation of multipartite Greenberger-Horne-Zeilinger (GHZ) state for neutral atoms. The result shows that a high fidelity better than 99% can be obtained within the state-of-the-art experiments.
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55
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Felser T, Notarnicola S, Montangero S. Efficient Tensor Network Ansatz for High-Dimensional Quantum Many-Body Problems. PHYSICAL REVIEW LETTERS 2021; 126:170603. [PMID: 33988416 DOI: 10.1103/physrevlett.126.170603] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 02/25/2021] [Indexed: 06/12/2023]
Abstract
We introduce a novel tensor network structure augmenting the well-established tree tensor network representation of a quantum many-body wave function. The new structure satisfies the area law in high dimensions remaining efficiently manipulatable and scalable. We benchmark this novel approach against paradigmatic two-dimensional spin models demonstrating unprecedented precision and system sizes. Finally, we compute the ground state phase diagram of two-dimensional lattice Rydberg atoms in optical tweezers observing nontrivial phases and quantum phase transitions, providing realistic benchmarks for current and future two-dimensional quantum simulations.
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Affiliation(s)
- Timo Felser
- Theoretische Physik, Universität des Saarlandes, D-66123 Saarbrücken, Germany
- Dipartimento di Fisica e Astronomia "G. Galilei", Università di Padova, I-35131 Padova, Italy
- INFN, Sezione di Padova, Via Marzolo 8, I-35131 Padova, Italy
| | - Simone Notarnicola
- Dipartimento di Fisica e Astronomia "G. Galilei", Università di Padova, I-35131 Padova, Italy
- INFN, Sezione di Padova, Via Marzolo 8, I-35131 Padova, Italy
- Padua Quantum Technology Research Center, Università di Padova, I-35131 Padova, Italy
| | - Simone Montangero
- Dipartimento di Fisica e Astronomia "G. Galilei", Università di Padova, I-35131 Padova, Italy
- INFN, Sezione di Padova, Via Marzolo 8, I-35131 Padova, Italy
- Padua Quantum Technology Research Center, Università di Padova, I-35131 Padova, Italy
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56
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Gehl M, Kindel W, Karl N, Orozco A, Musick K, Trotter D, Dallo C, Starbuck A, Leenheer A, DeRose C, Biedermann G, Jau YY, Lee J. Characterization of suspended membrane waveguides towards a photonic atom trap integrated platform. OPTICS EXPRESS 2021; 29:13129-13140. [PMID: 33985054 DOI: 10.1364/oe.418986] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 03/18/2021] [Indexed: 06/12/2023]
Abstract
We demonstrate an optical waveguide device, capable of supporting the high, in-vacuum, optical power necessary for trapping a single atom or a cold atom ensemble with evanescent fields. Our photonic integrated platform, with suspended membrane waveguides, successfully manages optical powers of 6 mW (500 μm span) to nearly 30 mW (125 μm span) over an un-tethered waveguide span. This platform is compatible with laser cooling and magneto-optical traps (MOTs) in the vicinity of the suspended waveguide, called the membrane MOT and the needle MOT, a key ingredient for efficient trap loading. We evaluate two novel designs that explore critical thermal management features that enable this large power handling. This work represents a significant step toward an integrated platform for coupling neutral atom quantum systems to photonic and electronic integrated circuits on silicon.
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57
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Jin Z, Gong WJ, Zhu AD, Zhang S, Qi Y, Su SL. Dissipative preparation of qutrit entanglement via periodically modulated Rydberg double antiblockade. OPTICS EXPRESS 2021; 29:10117-10133. [PMID: 33820145 DOI: 10.1364/oe.419568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 03/08/2021] [Indexed: 06/12/2023]
Abstract
We propose a mechanism of Rydberg double antiblockade by virtue of a resonant dipole-dipole interaction between a pair of Rydberg atoms placed at short distances scaling as 1/R3. By combining this novel excitation regime with microwave-driven fields and dissipative dynamics, a stationary qutrit entangled state can be obtained with high quality, the corresponding steady-state fidelity and purity are insensitive to the variations of the dynamical parameters. Furthermore, we introduce time-dependent laser fields with periodically modulated amplitude to speed up the entanglement creation process. Numerical simulations reveal that the order of magnitude of the shortened convergence time is about 103 in units of ω0, and the acceleration effect appears valid in broad parametric space. The present results enrich the physics of the Rydberg antiblockade regimes and may receive more attention for the experimental investigations in dissipative dynamics of neutral atoms.
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58
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Brady LT, Baldwin CL, Bapat A, Kharkov Y, Gorshkov AV. Optimal Protocols in Quantum Annealing and Quantum Approximate Optimization Algorithm Problems. PHYSICAL REVIEW LETTERS 2021; 126:070505. [PMID: 33666474 DOI: 10.1103/physrevlett.126.070505] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 12/21/2020] [Accepted: 01/26/2021] [Indexed: 06/12/2023]
Abstract
Quantum annealing (QA) and the quantum approximate optimization algorithm (QAOA) are two special cases of the following control problem: apply a combination of two Hamiltonians to minimize the energy of a quantum state. Which is more effective has remained unclear. Here we analytically apply the framework of optimal control theory to show that generically, given a fixed amount of time, the optimal procedure has the pulsed (or "bang-bang") structure of QAOA at the beginning and end but can have a smooth annealing structure in between. This is in contrast to previous works which have suggested that bang-bang (i.e., QAOA) protocols are ideal. To support this theoretical work, we carry out simulations of various transverse field Ising models, demonstrating that bang-anneal-bang protocols are more common. The general features identified here provide guideposts for the nascent experimental implementations of quantum optimization algorithms.
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Affiliation(s)
- Lucas T Brady
- Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, Maryland 20742, USA
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
| | - Christopher L Baldwin
- Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, Maryland 20742, USA
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
| | - Aniruddha Bapat
- Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, Maryland 20742, USA
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
| | - Yaroslav Kharkov
- Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, Maryland 20742, USA
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
| | - Alexey V Gorshkov
- Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, Maryland 20742, USA
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
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59
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Sun H, Song Y, Byun A, Jeong H, Ahn J. Imaging three-dimensional single-atom arrays all at once. OPTICS EXPRESS 2021; 29:4082-4090. [PMID: 33770995 DOI: 10.1364/oe.415805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 01/19/2021] [Indexed: 06/12/2023]
Abstract
Simultaneous imaging of a three-dimensional distribution of point sources is presented. In a two-lens microscope, the point-spreads on the quasi-image plane, which is located between the Fourier and image planes, are spatially distinct, so a set of Fresnel lenslets can perform individual wave-front shaping for axial and lateral rearrangements of the images. In experiments performed with single atoms and holographically programmed lenslets, various three-dimensional arrangements of point sources, including axially aligned atoms, are successfully refocused on the screen, demonstrating the simultaneous and time-efficient detection of the three-dimensional holographic imaging. We expect that non-sequential real-time measurements of three-dimensional point sources shall be in particular useful for quantum correlation measurements and in situ tracking of dynamic particles.
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60
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Samajdar R, Ho WW, Pichler H, Lukin MD, Sachdev S. Quantum phases of Rydberg atoms on a kagome lattice. Proc Natl Acad Sci U S A 2021; 118:e2015785118. [PMID: 33468679 PMCID: PMC7848540 DOI: 10.1073/pnas.2015785118] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We analyze the zero-temperature phases of an array of neutral atoms on the kagome lattice, interacting via laser excitation to atomic Rydberg states. Density-matrix renormalization group calculations reveal the presence of a wide variety of complex solid phases with broken lattice symmetries. In addition, we identify a regime with dense Rydberg excitations that has a large entanglement entropy and no local order parameter associated with lattice symmetries. From a mapping to the triangular lattice quantum dimer model, and theories of quantum phase transitions out of the proximate solid phases, we argue that this regime could contain one or more phases with topological order. Our results provide the foundation for theoretical and experimental explorations of crystalline and liquid states using programmable quantum simulators based on Rydberg atom arrays.
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Affiliation(s)
- Rhine Samajdar
- Department of Physics, Harvard University, Cambridge, MA 02138;
| | - Wen Wei Ho
- Department of Physics, Harvard University, Cambridge, MA 02138
- Department of Physics, Stanford University, Stanford, CA 94305
| | - Hannes Pichler
- Institute for Theoretical Physics, University of Innsbruck, Innsbruck A-6020, Austria
- Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Innsbruck A-6020, Austria
| | - Mikhail D Lukin
- Department of Physics, Harvard University, Cambridge, MA 02138
| | - Subir Sachdev
- Department of Physics, Harvard University, Cambridge, MA 02138;
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61
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Coherence enhancement in state transfer with seven-qubit superconducting processor. FUNDAMENTAL RESEARCH 2021. [DOI: 10.1016/j.fmre.2021.01.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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62
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Half-minute-scale atomic coherence and high relative stability in a tweezer clock. Nature 2020; 588:408-413. [PMID: 33328666 DOI: 10.1038/s41586-020-3009-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 09/17/2020] [Indexed: 11/09/2022]
Abstract
The preparation of large, low-entropy, highly coherent ensembles of identical quantum systems is fundamental for many studies in quantum metrology1, simulation2 and information3. However, the simultaneous realization of these properties remains a central challenge in quantum science across atomic and condensed-matter systems2,4-7. Here we leverage the favourable properties of tweezer-trapped alkaline-earth (strontium-88) atoms8-10, and introduce a hybrid approach to tailoring optical potentials that balances scalability, high-fidelity state preparation, site-resolved readout and preservation of atomic coherence. With this approach, we achieve trapping and optical-clock excited-state lifetimes exceeding 40 seconds in ensembles of approximately 150 atoms. This leads to half-minute-scale atomic coherence on an optical-clock transition, corresponding to quality factors well in excess of 1016. These coherence times and atom numbers reduce the effect of quantum projection noise to a level that is comparable with that of leading atomic systems, which use optical lattices to interrogate many thousands of atoms in parallel11,12. The result is a relative fractional frequency stability of 5.2(3) × 10-17τ-1/2 (where τ is the averaging time in seconds) for synchronous clock comparisons between sub-ensembles within the tweezer array. When further combined with the microscopic control and readout that are available in this system, these results pave the way towards long-lived engineered entanglement on an optical-clock transition13 in tailored atom arrays.
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63
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Xu Y, Chu J, Yuan J, Qiu J, Zhou Y, Zhang L, Tan X, Yu Y, Liu S, Li J, Yan F, Yu D. High-Fidelity, High-Scalability Two-Qubit Gate Scheme for Superconducting Qubits. PHYSICAL REVIEW LETTERS 2020; 125:240503. [PMID: 33412065 DOI: 10.1103/physrevlett.125.240503] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Accepted: 10/12/2020] [Indexed: 06/12/2023]
Abstract
High-quality two-qubit gate operations are crucial for scalable quantum information processing. Often, the gate fidelity is compromised when the system becomes more integrated. Therefore, a low-error-rate, easy-to-scale two-qubit gate scheme is highly desirable. Here, we experimentally demonstrate a new two-qubit gate scheme that exploits fixed-frequency qubits and a tunable coupler in a superconducting quantum circuit. The scheme requires less control lines, reduces cross talk effect, and simplifies calibration procedures, yet produces a controlled-Z gate in 30 ns with a high fidelity of 99.5%, derived from the interleaved randomized benchmarking method. Error analysis shows that gate errors are mostly coherence limited. Our demonstration paves the way for large-scale implementation of high-fidelity quantum operations.
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Affiliation(s)
- Yuan Xu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Ji Chu
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing, Jiangsu, 210093, China
| | - Jiahao Yuan
- Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Jiawei Qiu
- Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Yuxuan Zhou
- Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Libo Zhang
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Xinsheng Tan
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing, Jiangsu, 210093, China
| | - Yang Yu
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing, Jiangsu, 210093, China
| | - Song Liu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Jian Li
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Fei Yan
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Dapeng Yu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
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64
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Zhang H, Su QP, Yang CP. Efficient scheme for creating a W-type optical entangled coherent state. OPTICS EXPRESS 2020; 28:35622-35635. [PMID: 33379674 DOI: 10.1364/oe.411810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 10/30/2020] [Indexed: 06/12/2023]
Abstract
W-type optical entangled coherent states have important applications in quantum communication. Previous works require performing measurement in the preparation of such W states. We here propose an efficient scheme for creating a W-type optical entangled coherent state without measurement. This scheme employs a setup composed of three microwave cavities and a superconducting flux coupler qutrit. Because no measurement is required, the W state can be generated deterministically. In addition, the system complexity is greatly reduced because of using only one qutrit to couple the three cavities. Numerical analysis shows that within current experimental technology, the W state can be prepared with high fidelity. This scheme is universal and can be extended to create the W-type optical entangled coherent state, by using three microwave or optical cavities coupled via a three-level natural or artificial atom.
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65
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Pezzè L, Smerzi A. Heisenberg-Limited Noisy Atomic Clock Using a Hybrid Coherent and Squeezed State Protocol. PHYSICAL REVIEW LETTERS 2020; 125:210503. [PMID: 33274961 DOI: 10.1103/physrevlett.125.210503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 09/29/2020] [Indexed: 06/12/2023]
Abstract
We propose a hybrid quantum-classical atomic clock where the interrogation of atoms prepared in a spin-coherent (or weakly squeezed) state is used to feed back one or more highly spin-squeezed atomic states toward their optimal phase-sensitivity point. The hybrid clock overcomes the stability of a single Ramsey clock using coherent or optimal spin-squeezed states and reaches a Heisenberg-limited stability while avoiding nondestructive measurements. When optimized with respect to the total number of particles, the protocol surpasses the state-of-the-art proposals that use Greenberger-Horne-Zeilinger or NOON states. We compare analytical predictions with numerical simulations of clock operations, including correlated 1/f local oscillator noise.
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Affiliation(s)
- Luca Pezzè
- QSTAR, INO-CNR and LENS, Largo Enrico Fermi 2, 50125 Firenze, Italy
| | - Augusto Smerzi
- QSTAR, INO-CNR and LENS, Largo Enrico Fermi 2, 50125 Firenze, Italy
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66
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Mukherjee R, Xie H, Mintert F. Bayesian Optimal Control of Greenberger-Horne-Zeilinger States in Rydberg Lattices. PHYSICAL REVIEW LETTERS 2020; 125:203603. [PMID: 33258616 DOI: 10.1103/physrevlett.125.203603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 10/06/2020] [Indexed: 06/12/2023]
Abstract
The ability to prepare nonclassical states in a robust manner is essential for quantum sensors beyond the standard quantum limit. We demonstrate that Bayesian optimal control is capable of finding control pulses that drive trapped Rydberg atoms into highly entangled Greenberger-Horne-Zeilinger states. The control sequences have a physically intuitive functionality based on the quasi-integrability of the Ising dynamics. They can be constructed in laboratory experiments, resulting in preparation times that scale very favorably with the system size.
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Affiliation(s)
- Rick Mukherjee
- Department of Physics, Imperial College London, SW7 2AZ London, United Kingdom
| | - Harry Xie
- Department of Physics, Imperial College London, SW7 2AZ London, United Kingdom
| | - Florian Mintert
- Department of Physics, Imperial College London, SW7 2AZ London, United Kingdom
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67
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Zhang HX, Fan CH, Wu JH. In-phase and anti-phase entanglement dynamics of Rydberg atomic pairs. OPTICS EXPRESS 2020; 28:35350-35362. [PMID: 33182983 DOI: 10.1364/oe.408799] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 10/19/2020] [Indexed: 06/11/2023]
Abstract
We study the correlated evolutions of two far-spaced Rydberg atomic pairs with different resonant frequencies, interacting via van der Waals (vdW) potentials and driven by a common laser field. They are found to exhibit in-phase (anti-phase) beating dynamics characterized by identical (complementary) intra-pair entanglements under a specific condition in regard of inter-pair vdW potentials and driving field detunings. This occurs when each atomic pair just oscillates between its ground state and symmetric entangled state because its doubly excited state and asymmetric entangled state are forbidden due to rigid dipole blockade and perfect destructive interference, respectively. More importantly, optimal inter-pair overall entanglement can be attained at each beating node corresponding to semi-optimal intra-pair entanglements, and inevitable dissipation processes just result in a slow decay of intra-pair and inter-pair entanglements yet without destroying in-phase and anti-phase beating dynamics.
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68
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Besse JC, Reuer K, Collodo MC, Wulff A, Wernli L, Copetudo A, Malz D, Magnard P, Akin A, Gabureac M, Norris GJ, Cirac JI, Wallraff A, Eichler C. Realizing a deterministic source of multipartite-entangled photonic qubits. Nat Commun 2020; 11:4877. [PMID: 32985501 PMCID: PMC7522291 DOI: 10.1038/s41467-020-18635-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 09/04/2020] [Indexed: 11/23/2022] Open
Abstract
Sources of entangled electromagnetic radiation are a cornerstone in quantum information processing and offer unique opportunities for the study of quantum many-body physics in a controlled experimental setting. Generation of multi-mode entangled states of radiation with a large entanglement length, that is neither probabilistic nor restricted to generate specific types of states, remains challenging. Here, we demonstrate the fully deterministic generation of purely photonic entangled states such as the cluster, GHZ, and W state by sequentially emitting microwave photons from a controlled auxiliary system into a waveguide. We tomographically reconstruct the entire quantum many-body state for up to N = 4 photonic modes and infer the quantum state for even larger N from process tomography. We estimate that localizable entanglement persists over a distance of approximately ten photonic qubits.
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Affiliation(s)
| | - Kevin Reuer
- Department of Physics, ETH Zurich, Zurich, CH-8093, Switzerland
| | | | - Arne Wulff
- Department of Physics, ETH Zurich, Zurich, CH-8093, Switzerland
| | - Lucien Wernli
- Department of Physics, ETH Zurich, Zurich, CH-8093, Switzerland
| | - Adrian Copetudo
- Department of Physics, ETH Zurich, Zurich, CH-8093, Switzerland
| | - Daniel Malz
- Max-Planck-Institute of Quantum Optics, Hans-Kopfermann-Strasse 1, Garching, 85748, Germany
- Munich Center for Quantum Science and Technology, Schellingstrasse 4, München, 80799, Germany
| | - Paul Magnard
- Department of Physics, ETH Zurich, Zurich, CH-8093, Switzerland
| | - Abdulkadir Akin
- Department of Physics, ETH Zurich, Zurich, CH-8093, Switzerland
| | - Mihai Gabureac
- Department of Physics, ETH Zurich, Zurich, CH-8093, Switzerland
| | - Graham J Norris
- Department of Physics, ETH Zurich, Zurich, CH-8093, Switzerland
| | - J Ignacio Cirac
- Max-Planck-Institute of Quantum Optics, Hans-Kopfermann-Strasse 1, Garching, 85748, Germany
- Munich Center for Quantum Science and Technology, Schellingstrasse 4, München, 80799, Germany
| | - Andreas Wallraff
- Department of Physics, ETH Zurich, Zurich, CH-8093, Switzerland
- Quantum Center, ETH Zurich, Zurich, CH-8093, Switzerland
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69
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Stecker M, Nold R, Steinert LM, Grimmel J, Petrosyan D, Fortágh J, Günther A. Controlling the Dipole Blockade and Ionization Rate of Rydberg Atoms in Strong Electric Fields. PHYSICAL REVIEW LETTERS 2020; 125:103602. [PMID: 32955299 DOI: 10.1103/physrevlett.125.103602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 07/28/2020] [Indexed: 06/11/2023]
Abstract
We study a hitherto unexplored regime of the Rydberg excitation blockade using highly Stark-shifted, yet long-living, states of Rb atoms subject to electric fields above the classical ionization limit. Such states allow tuning the dipole-dipole interaction strength while their ionization rate can be changed over 2 orders of magnitude by small variations of the electric field. We demonstrate laser excitation of the interacting Rydberg states followed by their detection using controlled ionization and magnified imaging with high spatial and temporal resolution. Our work reveals new possibilities to engineer the interaction strength and dynamically control the ionization and detection of Rydberg atoms, which can be useful for realizing and assessing quantum simulators that vary in space and time.
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Affiliation(s)
- Markus Stecker
- Center for Quantum Science, Physikalisches Institut, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen, Germany
| | - Raphael Nold
- Center for Quantum Science, Physikalisches Institut, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen, Germany
| | - Lea-Marina Steinert
- Center for Quantum Science, Physikalisches Institut, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen, Germany
| | - Jens Grimmel
- Center for Quantum Science, Physikalisches Institut, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen, Germany
| | - David Petrosyan
- Center for Quantum Science, Physikalisches Institut, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen, Germany
- Institute of Electronic Structure and Laser, FORTH, GR-70013 Heraklion, Crete, Greece
| | - József Fortágh
- Center for Quantum Science, Physikalisches Institut, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen, Germany
| | - Andreas Günther
- Center for Quantum Science, Physikalisches Institut, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen, Germany
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70
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Cidrim A, do Espirito Santo TS, Schachenmayer J, Kaiser R, Bachelard R. Photon Blockade with Ground-State Neutral Atoms. PHYSICAL REVIEW LETTERS 2020; 125:073601. [PMID: 32857558 DOI: 10.1103/physrevlett.125.073601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 07/13/2020] [Indexed: 06/11/2023]
Abstract
We show that induced dipole-dipole interactions allow for photon blockade in subwavelength ensembles of two-level, ground-state neutral atoms. Our protocol relies on the energy shift of the single-excitation, superradiant state of N atoms, which can be engineered to yield an effective two-level system. A coherent pump induces Rabi oscillation between the ground state and a collective bright state, with at most a single excitation shared among all atoms. The possibility of using clock transitions that are long-lived and relatively robust against stray fields, alongside new prospects on experiments with subwavelength lattices, makes our proposal a promising alternative for quantum information protocols.
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Affiliation(s)
- A Cidrim
- Departamento de Física, Universidade Federal de São Carlos, Rod. Washington Luís, km 235-SP-310, 13565-905 São Carlos, SP, Brazil
| | - T S do Espirito Santo
- Instituto de Física de São Carlos, Universidade de São Paulo-13560-970 São Carlos, SP, Brazil
| | - J Schachenmayer
- IPCMS (UMR 7504) and ISIS (UMR 7006), Université de Strasbourg, CNRS, 67000 Strasbourg, France
| | - R Kaiser
- Université de Côte d'Azur, CNRS, Institut de Physique de Nice, 06560 Valbonne, France
| | - R Bachelard
- Departamento de Física, Universidade Federal de São Carlos, Rod. Washington Luís, km 235-SP-310, 13565-905 São Carlos, SP, Brazil
- Université de Côte d'Azur, CNRS, Institut de Physique de Nice, 06560 Valbonne, France
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71
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Moreno JR, Carleo G, Georges A. Deep Learning the Hohenberg-Kohn Maps of Density Functional Theory. PHYSICAL REVIEW LETTERS 2020; 125:076402. [PMID: 32857556 DOI: 10.1103/physrevlett.125.076402] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 07/14/2020] [Indexed: 06/11/2023]
Abstract
A striking consequence of the Hohenberg-Kohn theorem of density functional theory is the existence of a bijection between the local density and the ground-state many-body wave function. Here we study the problem of constructing approximations to the Hohenberg-Kohn map using a statistical learning approach. Using supervised deep learning with synthetic data, we show that this map can be accurately constructed for a chain of one-dimensional interacting spinless fermions in different phases of this model including the charge ordered Mott insulator and metallic phases and the critical point separating them. However, we also find that the learning is less effective across quantum phase transitions, suggesting an intrinsic difficulty in efficiently learning nonsmooth functional relations. We further study the problem of directly reconstructing complex observables from simple local density measurements, proposing a scheme amenable to statistical learning from experimental data.
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Affiliation(s)
- Javier Robledo Moreno
- Center for Computational Quantum Physics, Flatiron Institute, New York, New York 10010, USA
- Center for Quantum Phenomena, Department of Physics, New York University, 726 Broadway, New York, New York 10003, USA
| | - Giuseppe Carleo
- Center for Computational Quantum Physics, Flatiron Institute, New York, New York 10010, USA
| | - Antoine Georges
- Center for Computational Quantum Physics, Flatiron Institute, New York, New York 10010, USA
- Collège de France, 11 place Marcelin Berthelot, 75005 Paris, France
- CPHT, CNRS, École Polytechnique, IP Paris, F-91128 Palaiseau, France
- DQMP, Université de Genève, 24 quai Ernest Ansermet, CH-1211 Genève, Suisse
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72
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Gessner M, Smerzi A, Pezzè L. Multiparameter squeezing for optimal quantum enhancements in sensor networks. Nat Commun 2020; 11:3817. [PMID: 32733031 PMCID: PMC7393128 DOI: 10.1038/s41467-020-17471-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 06/12/2020] [Indexed: 11/09/2022] Open
Abstract
Squeezing currently represents the leading strategy for quantum enhanced precision measurements of a single parameter in a variety of continuous- and discrete-variable settings and technological applications. However, many important physical problems including imaging and field sensing require the simultaneous measurement of multiple unknown parameters. The development of multiparameter quantum metrology is yet hindered by the intrinsic difficulty in finding saturable sensitivity bounds and feasible estimation strategies. Here, we derive the general operational concept of multiparameter squeezing, identifying metrologically useful states and optimal estimation strategies. When applied to spin- or continuous-variable systems, our results generalize widely-used spin- or quadrature-squeezing parameters. Multiparameter squeezing provides a practical and versatile concept that paves the way to the development of quantum-enhanced estimation of multiple phases, gradients, and fields, and for the efficient characterization of multimode quantum states in atomic and optical sensor networks.
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Affiliation(s)
- Manuel Gessner
- Laboratoire Kastler Brossel, ENS-PSL Université, CNRS, Sorbonne Université, Collège de France, 24 Rue Lhomond, 75005, Paris, France.
| | - Augusto Smerzi
- QSTAR, CNR-INO and LENS, Largo Enrico Fermi 2, 50125, Firenze, Italy
| | - Luca Pezzè
- QSTAR, CNR-INO and LENS, Largo Enrico Fermi 2, 50125, Firenze, Italy
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73
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Mizoguchi M, Zhang Y, Kunimi M, Tanaka A, Takeda S, Takei N, Bharti V, Koyasu K, Kishimoto T, Jaksch D, Glaetzle A, Kiffner M, Masella G, Pupillo G, Weidemüller M, Ohmori K. Ultrafast Creation of Overlapping Rydberg Electrons in an Atomic BEC and Mott-Insulator Lattice. PHYSICAL REVIEW LETTERS 2020; 124:253201. [PMID: 32639753 DOI: 10.1103/physrevlett.124.253201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 04/20/2020] [Indexed: 06/11/2023]
Abstract
We study an array of ultracold atoms in an optical lattice (Mott insulator) excited with a coherent ultrashort laser pulse to a state where single-electron wave functions spatially overlap. Beyond a threshold principal quantum number where Rydberg orbitals of neighboring lattice sites overlap with each other, the atoms efficiently undergo spontaneous Penning ionization resulting in a drastic change of ion-counting statistics, sharp increase of avalanche ionization, and the formation of an ultracold plasma. These observations signal the actual creation of electronic states with overlapping wave functions, which is further confirmed by a significant difference in ionization dynamics between a Bose-Einstein condensate and a Mott insulator. This system is a promising platform for simulating electronic many-body phenomena dominated by Coulomb interactions in the condensed phase.
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Affiliation(s)
- M Mizoguchi
- Institute for Molecular Science, National Institutes of Natural Sciences, 38 Nishigo-Naka, Myodaiji, Okazaki, Aichi 444-8585, Japan
- SOKENDAI (The Graduate University for Advanced Studies), Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Y Zhang
- Institute for Molecular Science, National Institutes of Natural Sciences, 38 Nishigo-Naka, Myodaiji, Okazaki, Aichi 444-8585, Japan
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, and Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - M Kunimi
- Institute for Molecular Science, National Institutes of Natural Sciences, 38 Nishigo-Naka, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - A Tanaka
- Institute for Molecular Science, National Institutes of Natural Sciences, 38 Nishigo-Naka, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - S Takeda
- Institute for Molecular Science, National Institutes of Natural Sciences, 38 Nishigo-Naka, Myodaiji, Okazaki, Aichi 444-8585, Japan
- SOKENDAI (The Graduate University for Advanced Studies), Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - N Takei
- Institute for Molecular Science, National Institutes of Natural Sciences, 38 Nishigo-Naka, Myodaiji, Okazaki, Aichi 444-8585, Japan
- SOKENDAI (The Graduate University for Advanced Studies), Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - V Bharti
- Institute for Molecular Science, National Institutes of Natural Sciences, 38 Nishigo-Naka, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - K Koyasu
- Institute for Molecular Science, National Institutes of Natural Sciences, 38 Nishigo-Naka, Myodaiji, Okazaki, Aichi 444-8585, Japan
- SOKENDAI (The Graduate University for Advanced Studies), Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - T Kishimoto
- Department of Engineering Science and Institute for Advanced Science, University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585, Japan
| | - D Jaksch
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
- Center for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore
| | - A Glaetzle
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
- Center for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore
| | - M Kiffner
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
- Center for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore
| | - G Masella
- icFRC and ISIS (UMR 7006), Université de Strasbourg and CNRS, 67000 Strasbourg, France
| | - G Pupillo
- icFRC and ISIS (UMR 7006), Université de Strasbourg and CNRS, 67000 Strasbourg, France
| | - M Weidemüller
- Physikalisches Institut, Universität Heidelberg, Im Neuenheimer Feld 226, 69120 Heidelberg, Germany
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China and CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
| | - K Ohmori
- Institute for Molecular Science, National Institutes of Natural Sciences, 38 Nishigo-Naka, Myodaiji, Okazaki, Aichi 444-8585, Japan
- SOKENDAI (The Graduate University for Advanced Studies), Myodaiji, Okazaki, Aichi 444-8585, Japan
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74
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Mamaev M, Rey AM. Generating Multipartite Spin States with Fermionic Atoms in a Driven Optical Lattice. PHYSICAL REVIEW LETTERS 2020; 124:240401. [PMID: 32639830 DOI: 10.1103/physrevlett.124.240401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 05/12/2020] [Indexed: 06/11/2023]
Abstract
We propose a protocol for generating generalized Greenberger-Horne-Zeilinger (GHZ) states using ultracold fermions in 3D optical lattices or optical tweezer arrays. The protocol uses the interplay between laser driving, on site interactions and external trapping confinement to enforce energetic spin- and position-dependent constraints on the atomic motion. These constraints allow us to transform a local superposition into a GHZ state through a stepwise protocol that flips one site at a time. The protocol requires no site-resolved drives or spin-dependent potentials, exhibits robustness to slow global laser phase drift, and naturally makes use of the harmonic trap that would normally cause difficulties for entanglement-generating protocols in optical lattices. We also discuss an improved protocol that can compensate for holes in the loadout at the cost of increased generation time. The state can immediately be used for quantum-enhanced metrology in 3D optical lattice clocks, opening a window to push the sensitivity of state-of-the-art sensors beyond the standard quantum limit.
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Affiliation(s)
- Mikhail Mamaev
- JILA, NIST and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA and Center for Theory of Quantum Matter, University of Colorado, Boulder, Colorado 80309, USA
| | - Ana Maria Rey
- JILA, NIST and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA and Center for Theory of Quantum Matter, University of Colorado, Boulder, Colorado 80309, USA
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75
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Yang B, Sun H, Huang CJ, Wang HY, Deng Y, Dai HN, Yuan ZS, Pan JW. Cooling and entangling ultracold atoms in optical lattices. Science 2020; 369:550-553. [DOI: 10.1126/science.aaz6801] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 06/05/2020] [Indexed: 11/02/2022]
Abstract
Scalable, coherent many-body systems can enable the realization of previously unexplored quantum phases and have the potential to exponentially speed up information processing. Thermal fluctuations are negligible and quantum effects govern the behavior of such systems with extremely low temperature. We report the cooling of a quantum simulator with 10,000 atoms and mass production of high-fidelity entangled pairs. In a two-dimensional plane, we cool Mott insulator samples by immersing them into removable superfluid reservoirs, achieving an entropy per particle of 1.9−0.4+1.7×10−3kB. The atoms are then rearranged into a two-dimensional lattice free of defects. We further demonstrate a two-qubit gate with a fidelity of 0.993 ± 0.001 for entangling 1250 atom pairs. Our results offer a setting for exploring low-energy many-body phases and may enable the creation of large-scale entanglement.
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Affiliation(s)
- Bing Yang
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, 69120 Heidelberg, Germany
- CAS Centre for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Hui Sun
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, 69120 Heidelberg, Germany
- CAS Centre for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Chun-Jiong Huang
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Centre for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Han-Yi Wang
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, 69120 Heidelberg, Germany
- CAS Centre for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Youjin Deng
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Centre for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Han-Ning Dai
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, 69120 Heidelberg, Germany
- CAS Centre for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Zhen-Sheng Yuan
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, 69120 Heidelberg, Germany
- CAS Centre for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jian-Wei Pan
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, 69120 Heidelberg, Germany
- CAS Centre for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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76
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Alexander B, Bollinger JJ, Uys H. Generating Greenberger-Horne-Zeilinger states with squeezing and postselection. PHYSICAL REVIEW. A 2020; 101:10.1103/PhysRevA.101.062303. [PMID: 34796312 PMCID: PMC8597541 DOI: 10.1103/physreva.101.062303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Many quantum state preparation methods rely on a combination of dissipative quantum state initialization followed by unitary evolution to a desired target state. Here we demonstrate the usefulness of quantum measurement as an additional tool for quantum state preparation. Starting from a pure separable multipartite state, a control sequence, which includes rotation, spin squeezing via one-axis twisting, quantum measurement, and postselection, generates highly entangled multipartite states, which we refer to as projected squeezed (PS) states. Through an optimization method, we then identify parameters required to maximize the overlap fidelity of the PS states with the maximally entangled Greenberger-Horne-Zeilinger (GHZ) states. The method leads to an appreciable decrease in the state preparation time of GHZ states for successfully postselected outcomes when compared to preparation through unitary evolution with one-axis twisting only.
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Affiliation(s)
- Byron Alexander
- Department of Physics, Stellenbosch University, Stellenbosch Central 7600, Stellenbosch, South Africa
| | - John J. Bollinger
- National Institute of Standards and Technology, Boulder, Colorado 80305, USA
| | - Hermann Uys
- Department of Physics, Stellenbosch University, Stellenbosch Central 7600, Stellenbosch, South Africa
- Council for Scientific and Industrial Research, National Laser Centre, Brummeria, Pretoria 0184, South Africa
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77
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Lu YN, Zhang YR, Liu GQ, Nori F, Fan H, Pan XY. Observing Information Backflow from Controllable Non-Markovian Multichannels in Diamond. PHYSICAL REVIEW LETTERS 2020; 124:210502. [PMID: 32530656 DOI: 10.1103/physrevlett.124.210502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 04/20/2020] [Indexed: 06/11/2023]
Abstract
The unavoidable interaction of a quantum open system with its environment leads to the dissipation of quantum coherence and correlations, making its dynamical behavior a key role in many quantum technologies. In this Letter, we demonstrate the engineering of multiple dissipative channels by controlling the adjacent nuclear spins of a nitrogen-vacancy center in diamond. With a controllable non-Markovian dynamics of this open system, we observe that the quantum Fisher information flows to and from the environment using different noisy channels. Our work contributes to the developments of both noisy quantum metrology and quantum open systems from the viewpoints of metrologically useful entanglement.
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Affiliation(s)
- Ya-Nan Lu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yu-Ran Zhang
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
| | - Gang-Qin Liu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Franco Nori
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
- Physics Department, University of Michigan, Ann Arbor, Michigan 48109-1040, USA
| | - Heng Fan
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- CAS Center of Excellence in Topological Quantum Computation, Beijing 100190, China
| | - Xin-Yu Pan
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- CAS Center of Excellence in Topological Quantum Computation, Beijing 100190, China
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78
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Angaroni F, Graudenzi A, Rossignolo M, Maspero D, Calarco T, Piazza R, Montangero S, Antoniotti M. An Optimal Control Framework for the Automated Design of Personalized Cancer Treatments. Front Bioeng Biotechnol 2020; 8:523. [PMID: 32548108 PMCID: PMC7270334 DOI: 10.3389/fbioe.2020.00523] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 05/01/2020] [Indexed: 12/17/2022] Open
Abstract
One of the key challenges in current cancer research is the development of computational strategies to support clinicians in the identification of successful personalized treatments. Control theory might be an effective approach to this end, as proven by the long-established application to therapy design and testing. In this respect, we here introduce the Control Theory for Therapy Design (CT4TD) framework, which employs optimal control theory on patient-specific pharmacokinetics (PK) and pharmacodynamics (PD) models, to deliver optimized therapeutic strategies. The definition of personalized PK/PD models allows to explicitly consider the physiological heterogeneity of individuals and to adapt the therapy accordingly, as opposed to standard clinical practices. CT4TD can be used in two distinct scenarios. At the time of the diagnosis, CT4TD allows to set optimized personalized administration strategies, aimed at reaching selected target drug concentrations, while minimizing the costs in terms of toxicity and adverse effects. Moreover, if longitudinal data on patients under treatment are available, our approach allows to adjust the ongoing therapy, by relying on simplified models of cancer population dynamics, with the goal of minimizing or controlling the tumor burden. CT4TD is highly scalable, as it employs the efficient dCRAB/RedCRAB optimization algorithm, and the results are robust, as proven by extensive tests on synthetic data. Furthermore, the theoretical framework is general, and it might be applied to any therapy for which a PK/PD model can be estimated, and for any kind of administration and cost. As a proof of principle, we present the application of CT4TD to Imatinib administration in Chronic Myeloid leukemia, in which we adopt a simplified model of cancer population dynamics. In particular, we show that the optimized therapeutic strategies are diversified among patients, and display improvements with respect to the current standard regime.
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Affiliation(s)
- Fabrizio Angaroni
- Department of Informatics, Systems and Communication, University of Milan-Bicocca, Milan, Italy
| | - Alex Graudenzi
- Department of Informatics, Systems and Communication, University of Milan-Bicocca, Milan, Italy.,Institute of Molecular Bioimaging and Physiology, Consiglio Nazionale delle Ricerche (IBFM-CNR), Segrate, Milan, Italy
| | - Marco Rossignolo
- Center for Integrated Quantum Science and Technologies, Institute for Quantum Optics, Universitat Ulm, Ulm, Germany.,Istituto Nazionale di Fisica Nucleare (INFN), Padova, Italy
| | - Davide Maspero
- Department of Informatics, Systems and Communication, University of Milan-Bicocca, Milan, Italy.,Institute of Molecular Bioimaging and Physiology, Consiglio Nazionale delle Ricerche (IBFM-CNR), Segrate, Milan, Italy.,Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Tommaso Calarco
- Forschungszentrum Jülich, Institute of Quantum Control (PGI-8), Jülich, Germany
| | - Rocco Piazza
- Department of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.,Hematology and Clinical Research Unit, San Gerardo Hospital, Monza, Italy
| | - Simone Montangero
- Istituto Nazionale di Fisica Nucleare (INFN), Padova, Italy.,Department of Physics and Astronomy "G. Galilei", University of Padova, Padova, Italy
| | - Marco Antoniotti
- Department of Informatics, Systems and Communication, University of Milan-Bicocca, Milan, Italy.,Bicocca Bioinformatics Biostatistics and Bioimaging Centre - B4, Milan, Italy
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79
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Quantum entanglement between an atom and a molecule. Nature 2020; 581:273-277. [DOI: 10.1038/s41586-020-2257-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 03/02/2020] [Indexed: 02/03/2023]
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80
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Guo R, He X, Sheng C, Yang J, Xu P, Wang K, Zhong J, Liu M, Wang J, Zhan M. Balanced Coherence Times of Atomic Qubits of Different Species in a Dual 3×3 Magic-Intensity Optical Dipole Trap Array. PHYSICAL REVIEW LETTERS 2020; 124:153201. [PMID: 32357028 DOI: 10.1103/physrevlett.124.153201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 03/30/2020] [Indexed: 06/11/2023]
Abstract
We construct a polarization-mediated magic-intensity (MI) optical dipole trap (ODT) array, in which the detrimental effects of light shifts on the mixed-species qubits are efficiently mitigated so that the coherence times of the mixed-species qubits are both substantially enhanced and balanced for the first time. This mixed-species magic trapping technique relies on the tunability of the coefficient of the third-order cross term and ground state hyperpolarizability, which are inherently dependent on the degree of circular polarization of the trapping laser. Experimentally, polarization of the ODT array for ^{85}Rb qubits is finely adjusted to a definite value so that its working magnetic field required for magic trapping amounts to the one required for magically trapping ^{87}Rb qubits in another ODT array with fully circular polarization. Ultimately, in such a polarization-mediated MI-ODT array, the coherence times of ^{87}Rb and ^{85}Rb qubits are, respectively, enhanced up to 891±47 ms and 943±35 ms. Moreover, we reveal that the noise of the elliptic polarization causes dephasing effect on the ^{85}Rb qubits but it could be efficiently mitigated by choosing the dynamical range of active polarization device. We also show that light shifts seen by qubits in an elliptically polarized MI-ODT can be more efficiently compensated due to the decrease in the ground state hyperpolarizability. It is anticipated that the novel mixed-species MI-ODT array is a versatile platform for building scalable quantum computers with neutral atoms.
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Affiliation(s)
- Ruijun Guo
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, APM, Chinese Academy of Sciences, Wuhan 430071, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Xiaodong He
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, APM, Chinese Academy of Sciences, Wuhan 430071, China
- Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Cheng Sheng
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, APM, Chinese Academy of Sciences, Wuhan 430071, China
- Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Jiaheng Yang
- School of Mathematics and Physics, Qingdao University of Science and Technology, Qingdao 266061, China
| | - Peng Xu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, APM, Chinese Academy of Sciences, Wuhan 430071, China
- Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Kunpeng Wang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, APM, Chinese Academy of Sciences, Wuhan 430071, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Jiaqi Zhong
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, APM, Chinese Academy of Sciences, Wuhan 430071, China
- Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Min Liu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, APM, Chinese Academy of Sciences, Wuhan 430071, China
- Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Jin Wang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, APM, Chinese Academy of Sciences, Wuhan 430071, China
- Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Mingsheng Zhan
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, APM, Chinese Academy of Sciences, Wuhan 430071, China
- Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China
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81
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Li Y, Cai H, Wang DW, Li L, Yuan J, Li W. Many-Body Chiral Edge Currents and Sliding Phases of Atomic Spin Waves in Momentum-Space Lattice. PHYSICAL REVIEW LETTERS 2020; 124:140401. [PMID: 32338979 DOI: 10.1103/physrevlett.124.140401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 12/02/2019] [Accepted: 03/16/2020] [Indexed: 06/11/2023]
Abstract
Collective excitations (spin waves) of long-lived atomic hyperfine states can be synthesized into a Bose-Hubbard model in momentum space. We explore many-body ground states and dynamics of a two-leg momentum-space lattice formed by two coupled hyperfine states. Essential ingredients of this setting are a staggered artificial magnetic field engineered by lasers that couple the spin wave states and a state-dependent long-range interaction, which is induced by laser dressing a hyperfine state to a Rydberg state. The Rydberg dressed two-body interaction gives rise to a state-dependent blockade in momentum space and can amplify staggered flux-induced antichiral edge currents in the many-body ground state in the presence of magnetic flux. When the Rydberg dressing is applied to both hyperfine states, exotic sliding insulating and superfluid (supersolid) phases emerge. Because of the Rydberg dressed long-range interaction, spin waves slide along a leg of the momentum-space lattice without costing energy. Our study paves a route to the quantum simulation of topological phases and exotic dynamics with interacting spin waves of atomic hyperfine states in momentum-space lattice.
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Affiliation(s)
- Yongqiang Li
- Department of Physics, National University of Defense Technology, Changsha 410073, People's Republic of China
- Department of Physics, Graduate School of China Academy of Engineering Physics, Beijing 100193, People's Republic of China
| | - Han Cai
- Interdisciplinary Center for Quantum Information and State Key Laboratory of Modern Optical Instrumentation, Zhejiang Province Key Laboratory of Quantum Technology and Device and Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Da-Wei Wang
- Interdisciplinary Center for Quantum Information and State Key Laboratory of Modern Optical Instrumentation, Zhejiang Province Key Laboratory of Quantum Technology and Device and Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Lin Li
- MOE Key Laboratory of Fundamental Physical Quantities Measurement, Hubei Key Laboratory of Gravitation and Quantum Physics, PGMF and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Jianmin Yuan
- Department of Physics, National University of Defense Technology, Changsha 410073, People's Republic of China
- Department of Physics, Graduate School of China Academy of Engineering Physics, Beijing 100193, People's Republic of China
| | - Weibin Li
- School of Physics and Astronomy, and Centre for the Mathematics and Theoretical Physics of Quantum Non-equilibrium Systems, The University of Nottingham, Nottingham NG7 2RD, United Kingdom
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82
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Yoo SM, Javanainen J. Light reflection and transmission in planar lattices of cold atoms. OPTICS EXPRESS 2020; 28:9764-9776. [PMID: 32225577 DOI: 10.1364/oe.389570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 03/09/2020] [Indexed: 06/10/2023]
Abstract
Manipulation of light using atoms plays a fundamental and important role in emerging technologies such as integrated photonics, information storage, and quantum sensors. Specifically, there have been intense theoretical efforts involving large samples of cold neutral atoms for coherent control of light. Here we present a theoretical scheme that enables efficient computation of collective optical responses of mono- and bi-layer planar square lattices of dense, cold two-level atoms using classical electrodynamics of coupled dipoles in the limit of low laser intensity. The steady-state transmissivity and reflectivity are obtained at a field point far away from the atomic lattices in the regime with no Bragg reflection. While our earlier method was based on exact solution of the electrodynamics for a small-scale lattice, here we calculate the dipole moments assuming that they are the same at all lattice sites, as for an infinite lattice. Atomic lattices with effectively over one hundred times more sites than in our earlier exact computations can then be simulated numerically with fewer computational resources. We have implemented an automatic selection of the number of sites under the given convergence criteria. We compare the numerical results from both computational schemes. We also find similarities and differences of a stack of two atomic lattices from a two-atom sample. Such aspects may be exploited to engineer a stack for potential applications.
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83
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Samajdar R, Ho WW, Pichler H, Lukin MD, Sachdev S. Complex Density Wave Orders and Quantum Phase Transitions in a Model of Square-Lattice Rydberg Atom Arrays. PHYSICAL REVIEW LETTERS 2020; 124:103601. [PMID: 32216437 DOI: 10.1103/physrevlett.124.103601] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Accepted: 02/12/2020] [Indexed: 06/10/2023]
Abstract
We describe the zero-temperature phase diagram of a model of a two-dimensional square-lattice array of neutral atoms, excited into Rydberg states and interacting via strong van der Waals interactions. Using the density-matrix renormalization group algorithm, we map out the phase diagram and obtain a rich variety of phases featuring complex density wave orderings, upon varying lattice spacing and laser detuning. While some of these phases result from the classical optimization of the van der Waals energy, we also find intrinsically quantum-ordered phases stabilized by quantum fluctuations. These phases are surrounded by novel quantum phase transitions, which we analyze by finite-size scaling numerics and Landau theories. Our work highlights Rydberg quantum simulators in higher dimensions as promising platforms to realize exotic many-body phenomena.
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Affiliation(s)
- Rhine Samajdar
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Wen Wei Ho
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Hannes Pichler
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
- ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA
- Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, California 91125, USA
| | - Mikhail D Lukin
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Subir Sachdev
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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84
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Wintermantel TM, Wang Y, Lochead G, Shevate S, Brennen GK, Whitlock S. Unitary and Nonunitary Quantum Cellular Automata with Rydberg Arrays. PHYSICAL REVIEW LETTERS 2020; 124:070503. [PMID: 32142322 DOI: 10.1103/physrevlett.124.070503] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 01/29/2020] [Indexed: 06/10/2023]
Abstract
We propose a physical realization of quantum cellular automata (QCA) using arrays of ultracold atoms excited to Rydberg states. The key ingredient is the use of programmable multifrequency couplings which generalize the Rydberg blockade and facilitation effects to a broader set of nonadditive, unitary and nonunitary (dissipative) conditional interactions. Focusing on a 1D array we define a set of elementary QCA rules that generate complex and varied quantum dynamical behavior. Finally, we demonstrate theoretically that Rydberg QCA is ideally suited for variational quantum optimization protocols and quantum state engineering by finding parameters that generate highly entangled states as the steady state of the quantum dynamics.
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Affiliation(s)
- T M Wintermantel
- Physikalisches Institut, Universität Heidelberg, Im Neuenheimer Feld 226, 69120 Heidelberg, Germany
- ISIS (UMR 7006) and IPCMS (UMR 7504), University of Strasbourg and CNRS, 67000 Strasbourg, France
| | - Y Wang
- ISIS (UMR 7006) and IPCMS (UMR 7504), University of Strasbourg and CNRS, 67000 Strasbourg, France
| | - G Lochead
- ISIS (UMR 7006) and IPCMS (UMR 7504), University of Strasbourg and CNRS, 67000 Strasbourg, France
| | - S Shevate
- ISIS (UMR 7006) and IPCMS (UMR 7504), University of Strasbourg and CNRS, 67000 Strasbourg, France
| | - G K Brennen
- Center for Engineered Quantum Systems, Department of Physics & Astronomy, Macquarie University, 2109 New South Wales, Australia
| | - S Whitlock
- ISIS (UMR 7006) and IPCMS (UMR 7504), University of Strasbourg and CNRS, 67000 Strasbourg, France
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85
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Gambetta FM, Li W, Schmidt-Kaler F, Lesanovsky I. Engineering NonBinary Rydberg Interactions via Phonons in an Optical Lattice. PHYSICAL REVIEW LETTERS 2020; 124:043402. [PMID: 32058736 DOI: 10.1103/physrevlett.124.043402] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 12/17/2019] [Indexed: 06/10/2023]
Abstract
Coupling electronic and vibrational degrees of freedom of Rydberg atoms held in optical tweezer arrays offers a flexible mechanism for creating and controlling atom-atom interactions. We find that the state-dependent coupling between Rydberg atoms and local oscillator modes gives rise to two- and three-body interactions which are controllable through the strength of the local confinement. This approach even permits the cancellation of two-body terms such that three-body interactions become dominant. We analyze the structure of these interactions on two-dimensional bipartite lattice geometries and explore the impact of three-body interactions on system ground state on a square lattice. Focusing specifically on a system of ^{87}Rb atoms, we show that the effects of the multibody interactions can be maximized via a tailored dressed potential within a trapping frequency range of the order of a few hundred kilohertz and for temperatures corresponding to a >90% occupation of the atomic vibrational ground state. These parameters, as well as the multibody induced timescales, are compatible with state-of-the-art arrays of optical tweezers. Our work shows a highly versatile handle for engineering multibody interactions of quantum many-body systems in most recent manifestations on Rydberg lattice quantum simulators.
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Affiliation(s)
- F M Gambetta
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
- Centre for the Mathematics and Theoretical Physics of Quantum Non-equilibrium Systems, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - W Li
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
- Centre for the Mathematics and Theoretical Physics of Quantum Non-equilibrium Systems, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - F Schmidt-Kaler
- QUANTUM, Institut für Physik, Johannes Gutenberg-Universität Mainz, 55128 Mainz, Germany
- Helmholtz-Institut Mainz, 55128 Mainz, Germany
| | - I Lesanovsky
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
- Centre for the Mathematics and Theoretical Physics of Quantum Non-equilibrium Systems, University of Nottingham, Nottingham NG7 2RD, United Kingdom
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86
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Pezzè L, Gessner M, Feldmann P, Klempt C, Santos L, Smerzi A. Heralded Generation of Macroscopic Superposition States in a Spinor Bose-Einstein Condensate. PHYSICAL REVIEW LETTERS 2019; 123:260403. [PMID: 31951461 DOI: 10.1103/physrevlett.123.260403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 06/17/2019] [Indexed: 06/10/2023]
Abstract
Macroscopic superposition states enable fundamental tests of quantum mechanics and hold a huge potential in metrology, sensing, and other quantum technologies. We propose to generate macroscopic superposition states of a large number of atoms in the ground state of a spin-1 Bose-Einstein condensate. Measuring the number of particles in one mode prepares with large probability highly entangled macroscopic superposition states in the two remaining modes. The macroscopic superposition states are heralded by the measurement outcome. Our protocol is robust under realistic conditions in current experiments, including finite adiabaticity, particle loss, and measurement uncertainty.
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Affiliation(s)
- L Pezzè
- QSTAR, INO-CNR, and LENS, Largo Enrico Fermi 2, IT-50125 Firenze, Italy
| | - M Gessner
- QSTAR, INO-CNR, and LENS, Largo Enrico Fermi 2, IT-50125 Firenze, Italy
- Département de Physique, École Normale Supérieure, PSL Université, CNRS, 24 Rue Lhomond, 75005 Paris, France
| | - P Feldmann
- Institut für Theoretische Physik, Leibniz Universität Hannover, Appelstr. 2, DE-30167 Hannover, Germany
| | - C Klempt
- Institut für Quantenoptik, Leibniz Universität Hannover, Welfengarten 1, DE-30167 Hannover, Germany
| | - L Santos
- Institut für Theoretische Physik, Leibniz Universität Hannover, Appelstr. 2, DE-30167 Hannover, Germany
| | - A Smerzi
- QSTAR, INO-CNR, and LENS, Largo Enrico Fermi 2, IT-50125 Firenze, Italy
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87
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Cox KC, Meyer DH, Castillo ZA, Fatemi FK, Kunz PD. Spin-Wave Multiplexed Atom-Cavity Electrodynamics. PHYSICAL REVIEW LETTERS 2019; 123:263601. [PMID: 31951441 DOI: 10.1103/physrevlett.123.263601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Indexed: 06/10/2023]
Abstract
We introduce multiplexed atom-cavity quantum electrodynamics with an atomic ensemble coupled to a single optical cavity mode. Multiple Raman dressing beams establish cavity-coupled spin-wave excitations with distinctive spatial profiles. Experimentally, we demonstrate the concept by observing spin-wave vacuum Rabi splittings, selective superradiance, and interference in the cavity-mediated interactions of two spin waves. We highlight that the current experimental configuration allows rapid, interchangeable cavity coupling to 4 profiles with an overlap parameter of less than 10%, enough to demonstrate, for example, a quantum repeater network simulation in the cavity. With further improvements to the optical multiplexing setup, we infer the ability to access more than 10^{3} independent spin-wave profiles.
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Affiliation(s)
- Kevin C Cox
- U.S. Army Research Laboratory, 2800 Powder Mill Road, Adelphi, Maryland 20783, USA
| | - David H Meyer
- U.S. Army Research Laboratory, 2800 Powder Mill Road, Adelphi, Maryland 20783, USA
| | - Zachary A Castillo
- U.S. Army Research Laboratory, 2800 Powder Mill Road, Adelphi, Maryland 20783, USA
- Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - Fredrik K Fatemi
- U.S. Army Research Laboratory, 2800 Powder Mill Road, Adelphi, Maryland 20783, USA
| | - Paul D Kunz
- U.S. Army Research Laboratory, 2800 Powder Mill Road, Adelphi, Maryland 20783, USA
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88
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Wang H, Qin J, Ding X, Chen MC, Chen S, You X, He YM, Jiang X, You L, Wang Z, Schneider C, Renema JJ, Höfling S, Lu CY, Pan JW. Boson Sampling with 20 Input Photons and a 60-Mode Interferometer in a 10^{14}-Dimensional Hilbert Space. PHYSICAL REVIEW LETTERS 2019; 123:250503. [PMID: 31922765 DOI: 10.1103/physrevlett.123.250503] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 11/19/2019] [Indexed: 05/24/2023]
Abstract
Quantum computing experiments are moving into a new realm of increasing size and complexity, with the short-term goal of demonstrating an advantage over classical computers. Boson sampling is a promising platform for such a goal; however, the number of detected single photons is up to five so far, limiting these small-scale implementations to a proof-of-principle stage. Here, we develop solid-state sources of highly efficient, pure, and indistinguishable single photons and 3D integration of ultralow-loss optical circuits. We perform experiments with 20 pure single photons fed into a 60-mode interferometer. In the output, we detect up to 14 photons and sample over Hilbert spaces with a size up to 3.7×10^{14}, over 10 orders of magnitude larger than all previous experiments, which for the first time enters into a genuine sampling regime where it becomes impossible to exhaust all possible output combinations. The results are validated against distinguishable samplers and uniform samplers with a confidence level of 99.9%.
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Affiliation(s)
- Hui Wang
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, People's Republic of China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, People's Republic of China
| | - Jian Qin
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, People's Republic of China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, People's Republic of China
| | - Xing Ding
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, People's Republic of China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, People's Republic of China
| | - Ming-Cheng Chen
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, People's Republic of China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, People's Republic of China
| | - Si Chen
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, People's Republic of China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, People's Republic of China
| | - Xiang You
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, People's Republic of China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, People's Republic of China
| | - Yu-Ming He
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, People's Republic of China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, People's Republic of China
| | - Xiao Jiang
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, People's Republic of China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, People's Republic of China
| | - L You
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China
| | - Z Wang
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China
| | - C Schneider
- Technische Physik, Physikalisches Instität and Wilhelm Conrad Röntgen-Center for Complex Material Systems, Universitat Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Jelmer J Renema
- Adaptive Quantum Optics Group, Mesa+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, Netherlands
| | - Sven Höfling
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, People's Republic of China
- Technische Physik, Physikalisches Instität and Wilhelm Conrad Röntgen-Center for Complex Material Systems, Universitat Würzburg, Am Hubland, D-97074 Würzburg, Germany
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
| | - Chao-Yang Lu
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, People's Republic of China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, People's Republic of China
| | - Jian-Wei Pan
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, People's Republic of China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, People's Republic of China
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89
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Levine H, Keesling A, Semeghini G, Omran A, Wang TT, Ebadi S, Bernien H, Greiner M, Vuletić V, Pichler H, Lukin MD. Parallel Implementation of High-Fidelity Multiqubit Gates with Neutral Atoms. PHYSICAL REVIEW LETTERS 2019; 123:170503. [PMID: 31702233 DOI: 10.1103/physrevlett.123.170503] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Indexed: 06/10/2023]
Abstract
We report the implementation of universal two- and three-qubit entangling gates on neutral-atom qubits encoded in long-lived hyperfine ground states. The gates are mediated by excitation to strongly interacting Rydberg states and are implemented in parallel on several clusters of atoms in a one-dimensional array of optical tweezers. Specifically, we realize the controlled-phase gate, enacted by a novel, fast protocol involving only global coupling of two qubits to Rydberg states. We benchmark this operation by preparing Bell states with fidelity F≥95.0(2)%, and extract gate fidelity ≥97.4(3)%, averaged across five atom pairs. In addition, we report a proof-of-principle implementation of the three-qubit Toffoli gate, in which two control atoms simultaneously constrain the behavior of one target atom. These experiments demonstrate key ingredients for high-fidelity quantum information processing in a scalable neutral-atom platform.
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Affiliation(s)
- Harry Levine
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Alexander Keesling
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Giulia Semeghini
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Ahmed Omran
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Tout T Wang
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
- Department of Physics, Gordon College, Wenham, Massachusetts 01984, USA
| | - Sepehr Ebadi
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Hannes Bernien
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
| | - Markus Greiner
- 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
| | - Hannes Pichler
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
- ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA
| | - Mikhail D Lukin
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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90
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Entanglement in a 20-Qubit Superconducting Quantum Computer. Sci Rep 2019; 9:13465. [PMID: 31530848 PMCID: PMC6748943 DOI: 10.1038/s41598-019-49805-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 08/23/2019] [Indexed: 11/17/2022] Open
Abstract
The ability to prepare sizeable multi-qubit entangled states with full qubit control is a critical milestone for physical platforms upon which quantum computers are built. We investigate the extent to which entanglement is found within a prepared graph state on the 20-qubit superconducting quantum computer IBM Q Poughkeepsie. We prepared a graph state along a path consisting of all twenty qubits within the device and performed full quantum state tomography on all groups of four connected qubits along this path. We determined that each pair of connected qubits was inseparable and hence the prepared state was entangled. Additionally, a genuine multipartite entanglement witness was measured on all qubit subpaths of the graph state and we found genuine multipartite entanglement on chains of up to three qubits. These results represent a demonstration of entanglement in one of the largest solid-state qubit arrays to date and indicate the positive direction of progress towards the goal of implementing complex quantum algorithms relying on such effects.
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