1
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Nill C, Brandner K, Olmos B, Carollo F, Lesanovsky I. Many-Body Radiative Decay in Strongly Interacting Rydberg Ensembles. PHYSICAL REVIEW LETTERS 2022; 129:243202. [PMID: 36563275 DOI: 10.1103/physrevlett.129.243202] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 11/07/2022] [Indexed: 06/17/2023]
Abstract
When atoms are excited to high-lying Rydberg states they interact strongly with dipolar forces. The resulting state-dependent level shifts allow us to study many-body systems displaying intriguing nonequilibrium phenomena, such as constrained spin systems, and are at the heart of numerous technological applications, e.g., in quantum simulation and computation platforms. Here, we show that these interactions also have a significant impact on dissipative effects caused by the inevitable coupling of Rydberg atoms to the surrounding electromagnetic field. We demonstrate that their presence modifies the frequency of the photons emitted from the Rydberg atoms, making it dependent on the local neighborhood of the emitting atom. Interactions among Rydberg atoms thus turn spontaneous emission into a many-body process which manifests, in a thermodynamically consistent Markovian setting, in the emergence of collective jump operators in the quantum master equation governing the dynamics. We discuss how this collective dissipation-stemming from a mechanism different from the much studied superradiance and subradiance-accelerates decoherence and affects dissipative phase transitions in Rydberg ensembles.
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Affiliation(s)
- Chris Nill
- Institut für Theoretische Physik, Universität Tübingen, Auf der Morgenstelle 14, 72076 Tübingen, Germany
| | - Kay Brandner
- 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
| | - Beatriz Olmos
- Institut für Theoretische Physik, Universität Tübingen, Auf der Morgenstelle 14, 72076 Tübingen, Germany
- 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
| | - Federico Carollo
- Institut für Theoretische Physik, Universität Tübingen, Auf der Morgenstelle 14, 72076 Tübingen, Germany
| | - Igor Lesanovsky
- Institut für Theoretische Physik, Universität Tübingen, Auf der Morgenstelle 14, 72076 Tübingen, Germany
- 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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2
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Zhang Y, Barthel T. Criticality and Phase Classification for Quadratic Open Quantum Many-Body Systems. PHYSICAL REVIEW LETTERS 2022; 129:120401. [PMID: 36179179 DOI: 10.1103/physrevlett.129.120401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 08/15/2022] [Indexed: 06/16/2023]
Abstract
We study the steady states of translation-invariant open quantum many-body systems governed by Lindblad master equations, where the Hamiltonian is quadratic in the ladder operators, and the Lindblad operators are either linear or quadratic and Hermitian. These systems are called quasifree and quadratic, respectively. We find that steady states of one-dimensional systems with finite-range interactions necessarily have exponentially decaying Green's functions. For the quasifree case without quadratic Lindblad operators, we show that fermionic systems with finite-range interactions are noncritical for any number of spatial dimensions and provide bounds on the correlation lengths. Quasifree bosonic systems can be critical in D>1 dimensions. Last, we address the question of phase transitions in quadratic systems and find that, without symmetry constraints beyond invariance under single-particle basis and particle-hole transformations, all gapped Liouvillians belong to the same phase.
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Affiliation(s)
- Yikang Zhang
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
| | - Thomas Barthel
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
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3
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Mu WL, Li XX, Shao XQ. Cooling neutral atoms into maximal entanglement in the Rydberg blockade regime. OPTICS LETTERS 2022; 47:4491-4494. [PMID: 36048686 DOI: 10.1364/ol.471591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
We propose a cooling scheme to prepare stationary entanglement of neutral atoms in the Rydberg blockade regime by the combination of periodically collective laser pumping and dissipation. In each cycle, the controlled unitary dynamics process can selectively pump atoms away from the nontarget state while keeping the target state unchanged. The subsequent dissipative process redistributes the populations of ground states through the engineered spontaneous emission. After a number of cycles, the system will eventually be stabilized into the desired steady state, independent of the initial state. This protocol does not rely on coherent addressing of individual neutral atoms or fine control of Rydberg interaction intensity, which can, in principle, greatly improve the feasibility of experiments in related fields.
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4
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Singh VP, Weimer H. Driven-Dissipative Criticality within the Discrete Truncated Wigner Approximation. PHYSICAL REVIEW LETTERS 2022; 128:200602. [PMID: 35657854 DOI: 10.1103/physrevlett.128.200602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 04/14/2022] [Indexed: 06/15/2023]
Abstract
We present an approach to the numerical simulation of open quantum many-body systems based on the semiclassical framework of the discrete truncated Wigner approximation. We establish a quantum jump formalism to integrate the quantum master equation describing the dynamics of the system, which we find to be exact in both the noninteracting limit and the limit where the system is described by classical rate equations. We apply our method to simulation of the paradigmatic dissipative Ising model, where we are able to capture the critical fluctuations of the system beyond the level of mean-field theory.
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Affiliation(s)
- Vijay Pal Singh
- Institut für Theoretische Physik, Leibniz Universität Hannover, Appelstraße 2, 30167 Hannover, Germany
- Zentrum für Optische Quantentechnologien and Institut für Laserphysik, Universität Hamburg, 22761 Hamburg, Germany
| | - Hendrik Weimer
- Institut für Theoretische Physik, Leibniz Universität Hannover, Appelstraße 2, 30167 Hannover, Germany
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5
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Kumar K, Prasad V. Few generalized entropic relations related to Rydberg atoms. Sci Rep 2022; 12:7496. [PMID: 35523799 PMCID: PMC9076694 DOI: 10.1038/s41598-022-10854-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Accepted: 04/12/2022] [Indexed: 11/08/2022] Open
Abstract
We calculate the analytical and numerical values of the position space Shannon entropy, momentum space Shannon entropy, and total Shannon entropy, [Formula: see text], [Formula: see text], and [Formula: see text], respectively, of free and trapped Rydberg hydrogen-like atoms. The influence of atomic number Z, the principal quantum number n, and energy E on the Shannon entropy of the Rydberg atoms are illustrated. The scaling properties of Shannon entropy with energy of states E and the principal quantum number n have been reported for the first time to the best of our knowledge. Our work explains how Shannon entropy indicates localization-delocalization of the wavefunction. The total Shannon entropy as a measure of the number of nodes in the trapped Rydberg atom's wavefunction is also discussed. We show why an uncertainty relation based on Shannon entropy is superior to Heisenberg uncertainty for Rydberg atoms.
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Affiliation(s)
- Kirtee Kumar
- Department of Physics and Astrophysics, University of Delhi, Delhi, 110007, India
- Department of Physics, Motilal Nehru College, University of Delhi, Delhi, 110021, India
| | - Vinod Prasad
- Department of Physics, Swami Shraddhanand College, University of Delhi, Delhi, 110036, India.
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6
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Cole DC, Erickson SD, Zarantonello G, Horn KP, Hou PY, Wu JJ, Slichter DH, Reiter F, Koch CP, Leibfried D. Resource-Efficient Dissipative Entanglement of Two Trapped-Ion Qubits. PHYSICAL REVIEW LETTERS 2022; 128:080502. [PMID: 35275690 DOI: 10.1103/physrevlett.128.080502] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 12/02/2021] [Indexed: 06/14/2023]
Abstract
We demonstrate a simplified method for dissipative generation of an entangled state of two trapped-ion qubits. Our implementation produces its target state faster and with higher fidelity than previous demonstrations of dissipative entanglement generation and eliminates the need for auxiliary ions. The entangled singlet state is generated in ∼7 ms with a fidelity of 0.949(4). The dominant source of infidelity is photon scattering. We discuss this error source and strategies for its mitigation.
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Affiliation(s)
- Daniel C Cole
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - Stephen D Erickson
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Giorgio Zarantonello
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Karl P Horn
- Theoretische Physik, Universität Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
| | - Pan-Yu Hou
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Jenny J Wu
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Daniel H Slichter
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - Florentin Reiter
- Institute for Quantum Electronics, ETH Zürich, Otto-Stern-Weg 1, 8093 Zürich, Switzerland
| | - Christiane P Koch
- Theoretische Physik, Universität Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
- Dahlem Center for Complex Quantum Systems and Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Dietrich Leibfried
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
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7
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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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8
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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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9
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Wu JL, Su SL, Wang Y, Song J, Xia Y, Jiang YY. Effective Rabi dynamics of Rydberg atoms and robust high-fidelity quantum gates with a resonant amplitude-modulation field. OPTICS LETTERS 2020; 45:1200-1203. [PMID: 32108805 DOI: 10.1364/ol.386765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 01/18/2020] [Indexed: 06/10/2023]
Abstract
With a resonant amplitude-modulation field on two Rydberg atoms, we propose a Rydberg antiblockade (RAB) regime, where the Rabi oscillation between collective ground and excited states is induced. A controlled-Z gate can be yielded through a Rabi cycle. Further, several common issues of the RAB gates are solved by modifying the parameter relation. The gate fidelity and gate robustness against the control error are enhanced with a shaped pulse. The requirement of control precision of the Rydberg-Rydberg interaction strength is relaxed. In addition, the atomic excitation is restrained and therefore the gate robustness against atomic decay is enhanced.
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10
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Raghunandan M, Wolf F, Ospelkaus C, Schmidt PO, Weimer H. Initialization of quantum simulators by sympathetic cooling. SCIENCE ADVANCES 2020; 6:eaaw9268. [PMID: 32181335 PMCID: PMC7060053 DOI: 10.1126/sciadv.aaw9268] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 12/11/2019] [Indexed: 06/10/2023]
Abstract
Simulating computationally intractable many-body problems on a quantum simulator holds great potential to deliver insights into physical, chemical, and biological systems. While the implementation of Hamiltonian dynamics within a quantum simulator has already been demonstrated in many experiments, the problem of initialization of quantum simulators to a suitable quantum state has hitherto remained mostly unsolved. Here, we show that already a single dissipatively driven auxiliary particle can efficiently prepare the quantum simulator in a low-energy state of largely arbitrary Hamiltonians. We demonstrate the scalability of our approach and show that it is robust against unwanted sources of decoherence. While our initialization protocol is largely independent of the physical realization of the simulation device, we provide an implementation example for a trapped ion quantum simulator.
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Affiliation(s)
- Meghana Raghunandan
- Institut für Theoretische Physik, Leibniz Universität Hannover, Appelstraβe 2, 30167 Hannover, Germany
| | - Fabian Wolf
- QUEST Institut, Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - Christian Ospelkaus
- QUEST Institut, Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
- Institut für Quantenoptik, Leibniz Universität Hannover, Welfengarten 1, 30167 Hannover, Germany
| | - Piet O. Schmidt
- QUEST Institut, Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
- Institut für Quantenoptik, Leibniz Universität Hannover, Welfengarten 1, 30167 Hannover, Germany
| | - Hendrik Weimer
- Institut für Theoretische Physik, Leibniz Universität Hannover, Appelstraβe 2, 30167 Hannover, Germany
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11
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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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12
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Li DX, Liao XM, Shao XQ. One-way quantum state transfer in a lossy coupled-cavity array. OPTICS EXPRESS 2019; 27:35971-35980. [PMID: 31878761 DOI: 10.1364/oe.27.035971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 11/11/2019] [Indexed: 06/10/2023]
Abstract
Quantum state transfer plays an important role in quantum information processing, and it has been obtained many of the theoretical and experimental triumphs. But designing a dissipation-assisted scheme to transfer a quantum state is still by no means trivial. Here we put forward an easier scheme to dissipatively transfer an arbitrary quantum state from a sender to a receiver with two four-level atoms and three lasers in a lossy coupled-cavity array, and make the quantum state stable at the receiver via the photon loss of optical cavities. Owing to the assistance of the dissipation, the target state becomes the steady state of the whole process. Thus there is no requirement on external time-dependent controls. Furthermore, the atomic spontaneous emission can be significantly suppressed as the adiabatic elimination of the excited states. We also discuss the experimental feasibility of this scheme with the current experimental technologies and a high fidelity of the transferred state in the receiver can be above 98%.
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13
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Li DX, Zheng TY, Shao XQ. Adiabatic preparation of Multipartite GHZ states via Rydberg ground-state blockade. OPTICS EXPRESS 2019; 27:20874-20885. [PMID: 31510175 DOI: 10.1364/oe.27.020874] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 06/24/2019] [Indexed: 06/10/2023]
Abstract
The multipartite GHZ states are useful resources for quantum information processing. Here we put forward a scalable way to adiabatically prepare the multipartite GHZ states in a chain of Rydberg atoms. Building on the ground-state blockade effect of Rydberg atoms and the stimulated Raman adiabatic passage (STIRAP), we suppress the adverse effect of the atomic spontaneous emission, and obtain a high fidelity of the multipartite GHZ states without requirements on the operational time. After investigating the feasibility of the proposal, we show a 3-qubit GHZ state can be generated in a wide range of relevant parameters and a fidelity above $98\%$98% is achievable with the current experimental technologies.
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14
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Li DX, Shao XQ, Wu JH, Yi XX, Zheng TY. Engineering steady Knill-Laflamme-Milburn state of Rydberg atoms by dissipation. OPTICS EXPRESS 2018; 26:2292-2302. [PMID: 29401769 DOI: 10.1364/oe.26.002292] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 01/16/2018] [Indexed: 06/07/2023]
Abstract
The Knill-Laflamme-Milburn (KLM) states have been proved to be a useful resource for quantum information processing [Nature409, 46 (2001)]. For atomic KLM states, several schemes have been put forward based on the time-dependent unitary dynamics, but the dissipative generation of these states has not been reported. This work discusses the possibility for creating different forms of bipartite KLM states in neutral atom system, where the spontaneous emission of excited Rydberg states, combined with the Rydberg antiblockade mechanism, is actively exploited to engineer a steady KLM state from an arbitrary initial state. The numerical simulation of the master equation signifies that a fidelity above 99% is available with the current experimental parameters.
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15
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Generation of steady entanglement via unilateral qubit driving in bad cavities. Sci Rep 2017; 7:17648. [PMID: 29247250 PMCID: PMC5732200 DOI: 10.1038/s41598-017-17933-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 11/28/2017] [Indexed: 11/08/2022] Open
Abstract
We propose a scheme for generating an entangled state for two atoms trapped in two separate cavities coupled to each other. The scheme is based on the competition between the unitary dynamics induced by the classical fields and the collective decays induced by the dissipation of two non-local bosonic modes. In this scheme, only one qubit is driven by external classical fields, whereas the other need not be manipulated via classical driving. This is meaningful for experimental implementation between separate nodes of a quantum network. The steady entanglement can be obtained regardless of the initial state, and the robustness of the scheme against parameter fluctuations is numerically demonstrated. We also give an analytical derivation of the stationary fidelity to enable a discussion of the validity of this regime. Furthermore, based on the dissipative entanglement preparation scheme, we construct a quantum state transfer setup with multiple nodes as a practical application.
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16
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Zhao YJ, Liu B, Ji YQ, Tang SQ, Shao XQ. Robust generation of entangled state via ground-state antiblockade of Rydberg atoms. Sci Rep 2017; 7:16489. [PMID: 29184192 PMCID: PMC5705668 DOI: 10.1038/s41598-017-16533-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 11/15/2017] [Indexed: 11/20/2022] Open
Abstract
We propose a mechanism of ground-state antiblockade of Rydberg atoms, which is then exploited to prepare two-atom entangled state via three different kinds of pulses. First we use the pulses in the form of sin2 and cos2 functions and obtain a maximally entangled state at an accurate interaction time. Then the method of stimulated Raman adiabatic passage (STIRAP) is adopted for the entanglement generation, which is immune to the fluctuations of revelent parameters but requires a long time. Finally we capitalize the advantages of the former two methods and employ shortcuts to adiabatic passage (STAP) to generate the maximal entanglement. The strictly numerical simulation reveals that the current scheme is robust against spontaneous emission of atoms due to the virtual excitation of Rydberg states, and all of the above methods favor a high fidelity with the present experimental technology.
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Affiliation(s)
- Y J Zhao
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun, 130024, People's Republic of China
- Center for Advanced Optoelectronic Functional Materials Research, and Key Laboratory for UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun, 130024, People's Republic of China
| | - B Liu
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun, 130024, People's Republic of China
- Center for Advanced Optoelectronic Functional Materials Research, and Key Laboratory for UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun, 130024, People's Republic of China
| | - Y Q Ji
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun, 130024, People's Republic of China
- Center for Advanced Optoelectronic Functional Materials Research, and Key Laboratory for UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun, 130024, People's Republic of China
| | - S Q Tang
- Department of Physics and Electronic Information Science, Hengyang Normal University, Hengyang, 421008, People's Republic of China.
| | - X Q Shao
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun, 130024, People's Republic of China.
- Center for Advanced Optoelectronic Functional Materials Research, and Key Laboratory for UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun, 130024, People's Republic of China.
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17
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Li DX, Shao XQ, Wu JH, Yi XX. Engineering steady-state entanglement via dissipation and quantum Zeno dynamics in an optical cavity. OPTICS LETTERS 2017; 42:3904-3907. [PMID: 28957157 DOI: 10.1364/ol.42.003904] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 09/05/2017] [Indexed: 06/07/2023]
Abstract
A new mechanism is proposed for dissipatively preparing maximal Bell entangled state of two atoms in an optical cavity. This scheme integrates the spontaneous emission, the light shift of atoms in the presence of dispersive microwave field, and the quantum Zeno dynamics induced by continuous coupling, to obtain a unique steady state irrespective of initial state. Even for a large cavity decay, a high-fidelity entangled state is achievable at a short convergence time, since the occupation of the cavity mode is inhibited by the Zeno requirement. Therefore, a low single-atom cooperativity C=g2/(κγ) is good enough for realizing a high fidelity of entanglement in a wide range of decoherence parameters. As a straightforward extension, the feasibility for preparation of two-atom Knill-Laflamme-Milburn state with the same mechanism is also discussed.
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18
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Smelyanskiy VN, Venturelli D, Perdomo-Ortiz A, Knysh S, Dykman MI. Quantum Annealing via Environment-Mediated Quantum Diffusion. PHYSICAL REVIEW LETTERS 2017; 118:066802. [PMID: 28234537 DOI: 10.1103/physrevlett.118.066802] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Indexed: 06/06/2023]
Abstract
We show that quantum diffusion near a quantum critical point can provide an efficient mechanism of quantum annealing. It is based on the diffusion-mediated recombination of excitations in open systems far from thermal equilibrium. We find that, for an Ising spin chain coupled to a bosonic bath and driven by a monotonically decreasing transverse field, excitation diffusion sharply slows down below the quantum critical region. This leads to spatial correlations and effective freezing of the excitation density. Still, obtaining an approximate solution of an optimization problem via the diffusion-mediated quantum annealing can be faster than via closed-system quantum annealing or Glauber dynamics.
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Affiliation(s)
| | - Davide Venturelli
- USRA Research Institute for Advanced Computer Science (RIACS), Mountain View, California 94043, USA
- NASA Ames Research Center, Mail Stop 269-1, Moffett Field, California 94035-1000, USA
| | - Alejandro Perdomo-Ortiz
- USRA Research Institute for Advanced Computer Science (RIACS), Mountain View, California 94043, USA
- NASA Ames Research Center, Mail Stop 269-1, Moffett Field, California 94035-1000, USA
| | - Sergey Knysh
- NASA Ames Research Center, Mail Stop 269-1, Moffett Field, California 94035-1000, USA
- Stinger Ghaffarian Technologies Inc., 7701 Greenbelt Road, Suite 400, Greenbelt, Maryland 20770, USA
| | - Mark I Dykman
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824-2320, USA
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Marcuzzi M, Minář J, Barredo D, de Léséleuc S, Labuhn H, Lahaye T, Browaeys A, Levi E, Lesanovsky I. Facilitation Dynamics and Localization Phenomena in Rydberg Lattice Gases with Position Disorder. PHYSICAL REVIEW LETTERS 2017; 118:063606. [PMID: 28234523 DOI: 10.1103/physrevlett.118.063606] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Indexed: 06/06/2023]
Abstract
We explore the dynamics of Rydberg excitations in an optical tweezer array under antiblockade (or facilitation) conditions. Because of the finite temperature the atomic positions are randomly spread, an effect that leads to quenched correlated disorder in the interatomic interaction strengths. This drastically affects the facilitation dynamics as we demonstrate experimentally on the elementary example of two atoms. To shed light on the role of disorder in a many-body setting we show that here the dynamics is governed by an Anderson-Fock model, i.e., an Anderson model formulated on a lattice with sites corresponding to many-body Fock states. We first consider a one-dimensional atom chain in a limit that is described by a one-dimensional Anderson-Fock model with disorder on every other site, featuring both localized and delocalized states. We then illustrate the effect of disorder experimentally in a situation in which the system maps on a two-dimensional Anderson-Fock model on a trimmed square lattice. We observe a clear suppression of excitation propagation, which we ascribe to the localization of the many-body wave functions in Hilbert space.
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Affiliation(s)
- Matteo Marcuzzi
- 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
| | - Jiří Minář
- 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
| | - Daniel Barredo
- Laboratoire Charles Fabry, Institut d'Optique Graduate School, CNRS, Université Paris-Saclay, 91127 Palaiseau cedex, France
| | - Sylvain de Léséleuc
- Laboratoire Charles Fabry, Institut d'Optique Graduate School, CNRS, Université Paris-Saclay, 91127 Palaiseau cedex, France
| | - Henning Labuhn
- Laboratoire Charles Fabry, Institut d'Optique Graduate School, CNRS, Université Paris-Saclay, 91127 Palaiseau cedex, France
| | - Thierry Lahaye
- Laboratoire Charles Fabry, Institut d'Optique Graduate School, CNRS, Université Paris-Saclay, 91127 Palaiseau cedex, France
| | - Antoine Browaeys
- Laboratoire Charles Fabry, Institut d'Optique Graduate School, CNRS, Université Paris-Saclay, 91127 Palaiseau cedex, France
| | - Emanuele Levi
- 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
| | - Igor 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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20
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Jin Z, Su SL, Zhu AD, Wang HF, Zhang S. Dissipative preparation of distributed steady entanglement: an approach of unilateral qubit driving. OPTICS EXPRESS 2017; 25:88-101. [PMID: 28085813 DOI: 10.1364/oe.25.000088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We propose a nonlocal scheme for preparing a distributed steady-state entanglement of two atoms trapped in separate optical cavities coupled through an optical fiber based on the combined effect of the unitary dynamics and dissipative process. In this scheme, only the qubit of one node is driven by an external classical field, while the other one does not need to be manipulated by an external field. This is meaningful for long distance quantum information processing tasks, and the experimental implementation is greatly simplified due to the unilateral manipulation on one node and the process of entanglement distribution can be avoided. This guarantees the absolute security of long distance quantum information processing tasks and makes the scheme more robust than that based on the unitary dynamics. We introduce the purity to characterize the mixture degree of the target steady-state. The steady entanglement can be obtained independent of the initial state. Furthermore, based on the dissipative entanglement preparation scheme, we construct a quantum teleportation setup with multiple nodes as a practical application, and the numerical simulation demonstrates the scheme can be realized effectively under the current experimental conditions..
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21
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Reiter F, Reeb D, Sørensen AS. Scalable Dissipative Preparation of Many-Body Entanglement. PHYSICAL REVIEW LETTERS 2016; 117:040501. [PMID: 27494463 DOI: 10.1103/physrevlett.117.040501] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Indexed: 06/06/2023]
Abstract
We present a technique for the dissipative preparation of highly entangled multiparticle states of atoms coupled to common oscillator modes. By combining local spontaneous emission with coherent couplings, we engineer many-body dissipation that drives the system from an arbitrary initial state into a Greenberger-Horne-Zeilinger state. We demonstrate that using our technique highly entangled steady states can be prepared efficiently in a time that scales polynomially with the system size. Our protocol assumes generic couplings and will thus enable the dissipative production of multiparticle entanglement in a wide range of physical systems. As an example, we demonstrate the feasibility of our scheme in state-of-the-art trapped-ion systems.
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Affiliation(s)
- Florentin Reiter
- Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen, Denmark
| | - David Reeb
- Institute for Theoretical Physics, Leibniz Universität Hannover, Appelstrasse 2, 30167 Hannover, Germany
| | - Anders S Sørensen
- Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen, Denmark
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22
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Morigi G, Eschner J, Cormick C, Lin Y, Leibfried D, Wineland DJ. Dissipative Quantum Control of a Spin Chain. PHYSICAL REVIEW LETTERS 2015; 115:200502. [PMID: 26613425 DOI: 10.1103/physrevlett.115.200502] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Indexed: 06/05/2023]
Abstract
A protocol is discussed for preparing a spin chain in a generic many-body state in the asymptotic limit of tailored nonunitary dynamics. The dynamics require the spectral resolution of the target state, optimized coherent pulses, engineered dissipation, and feedback. As an example, we discuss the preparation of an entangled antiferromagnetic state, and argue that the procedure can be applied to chains of trapped ions or Rydberg atoms.
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Affiliation(s)
- Giovanna Morigi
- Theoretische Physik, Universität des Saarlandes, D-66123 Saarbrücken, Germany
| | - Jürgen Eschner
- Experimentalphysik, Universität des Saarlandes, D-66123 Saarbrücken, Germany
| | - Cecilia Cormick
- IFEG, CONICET and Universidad Nacional de Córdoba, Ciudad Universitaria, X5016LAE Córdoba, Argentina
| | - Yiheng Lin
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - Dietrich Leibfried
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - David J Wineland
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
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23
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Implementation of quantum state manipulation in a dissipative cavity. Sci Rep 2015; 5:10656. [PMID: 26095355 PMCID: PMC5378870 DOI: 10.1038/srep10656] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 04/20/2015] [Indexed: 11/09/2022] Open
Abstract
We discuss a method to perform dissipation-assisted quantum state manipulation in a cavity. We show that atomic spontaneous emission and cavity decay might be exploited to drive many atoms into many-body steady-state entanglement. Our protocol offers a dramatic improvement in fidelity when noise strength increases. Moreover, the dephasing noise is suppressed effectively by showing that high-fidelity target state can be obtained in a dissipative environment.
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24
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Weimer H. Variational principle for steady states of dissipative quantum many-body systems. PHYSICAL REVIEW LETTERS 2015; 114:040402. [PMID: 25679882 DOI: 10.1103/physrevlett.114.040402] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Indexed: 06/04/2023]
Abstract
We present a novel generic framework to approximate the nonequilibrium steady states of dissipative quantum many-body systems. It is based on the variational minimization of a suitable norm of the quantum master equation describing the dynamics. We show how to apply this approach to different classes of variational quantum states and demonstrate its successful application to a dissipative extension of the Ising model, which is of importance to ongoing experiments on ultracold Rydberg atoms, as well as to a driven-dissipative variant of the Bose-Hubbard model. Finally, we identify several advantages of the variational approach over previously employed mean-field-like methods.
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Affiliation(s)
- Hendrik Weimer
- Institut für Theoretische Physik, Leibniz Universität Hannover, Appelstrasse 2, 30167 Hannover, Germany
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25
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Su SL, Shao XQ, Wang HF, Zhang S. Preparation of three-dimensional entanglement for distant atoms in coupled cavities via atomic spontaneous emission and cavity decay. Sci Rep 2014; 4:7566. [PMID: 25523944 PMCID: PMC4271254 DOI: 10.1038/srep07566] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 12/01/2014] [Indexed: 11/15/2022] Open
Abstract
We propose a dissipative scheme to prepare a three-dimensional entangled state for two atoms trapped in separate coupled cavities. Our work shows that both atomic spontaneous emission and cavity decay, which are two typical obstacles in unitary-dynamics-based schemes, are no longer detrimental, but necessary for three-dimensional entangled state preparation without specifying initial state and controlling the evolution time precisely. Final numerical simulation with one group of experimental parameters indicates that the performance of our scheme could be better than the unitary-dynamics-based scheme.
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Affiliation(s)
- Shi-Lei Su
- Department of Physics, Harbin Institute of Technology, Harbin 150001, China
- Department of Physics, College of Science, YanBian University, Yanji, Jilin 133002, China
| | - Xiao-Qiang Shao
- Centre for Quantum Sciences and School of Physics, Northeast Normal University, Changchun 130024, China
- Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore, 117543
| | - Hong-Fu Wang
- Department of Physics, College of Science, YanBian University, Yanji, Jilin 133002, China
| | - Shou Zhang
- Department of Physics, Harbin Institute of Technology, Harbin 150001, China
- Department of Physics, College of Science, YanBian University, Yanji, Jilin 133002, China
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26
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Ramos T, Pichler H, Daley AJ, Zoller P. Quantum spin dimers from chiral dissipation in cold-atom chains. PHYSICAL REVIEW LETTERS 2014; 113:237203. [PMID: 25526153 DOI: 10.1103/physrevlett.113.237203] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Indexed: 06/04/2023]
Abstract
We consider the nonequilibrium dynamics of a driven dissipative spin chain with chiral coupling to a one-dimensional (1D) bosonic bath, and its atomic implementation with a two-species mixture of cold quantum gases. The reservoir is represented by a spin-orbit coupled 1D quasicondensate of atoms in a magnetized phase, while the spins are identified with motional states of a separate species of atoms in an optical lattice. The chirality of reservoir excitations allows the spins to couple differently to left- and right-moving modes, which in our atomic setup can be tuned from bidirectional to purely unidirectional. Remarkably, this leads to a pure steady state in which pairs of neighboring spins form dimers that decouple from the remainder of the chain. Our results also apply to current experiments with two-level emitters coupled to photonic waveguides.
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Affiliation(s)
- Tomás Ramos
- Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, 6020 Innsbruck, Austria and Institute for Theoretical Physics, University of Innsbruck, 6020 Innsbruck, Austria
| | - Hannes Pichler
- Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, 6020 Innsbruck, Austria and Institute for Theoretical Physics, University of Innsbruck, 6020 Innsbruck, Austria
| | - Andrew J Daley
- Department of Physics and SUPA, University of Strathclyde, Glasgow G4 0NG, United Kingdom and Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Peter Zoller
- Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, 6020 Innsbruck, Austria and Institute for Theoretical Physics, University of Innsbruck, 6020 Innsbruck, Austria
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27
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Lee TE, Chan CK, Wang S. Entanglement tongue and quantum synchronization of disordered oscillators. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:022913. [PMID: 25353551 DOI: 10.1103/physreve.89.022913] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Indexed: 06/04/2023]
Abstract
We study the synchronization of dissipatively coupled van der Pol oscillators in the quantum limit, when each oscillator is near its quantum ground state. Two quantum oscillators with different frequencies exhibit an entanglement tongue, which is the quantum analog of an Arnold tongue. It means that the oscillators are entangled in steady state when the coupling strength is greater than a critical value, and the critical coupling increases with detuning. An ensemble of many oscillators with random frequencies still exhibits a synchronization phase transition in the quantum limit, and we analytically calculate how the critical coupling depends on the frequency disorder. Our results can be experimentally observed with trapped ions or neutral atoms.
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Affiliation(s)
- Tony E Lee
- ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA and Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Ching-Kit Chan
- ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA and Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Shenshen Wang
- Department of Physics and Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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28
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Rao DDB, Mølmer K. Dark entangled steady states of interacting Rydberg atoms. PHYSICAL REVIEW LETTERS 2013; 111:033606. [PMID: 23909321 DOI: 10.1103/physrevlett.111.033606] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Indexed: 06/02/2023]
Abstract
We propose a scheme for rapid generation of high fidelity steady-state entanglement between a pair of atoms. A two-photon excitation process toward long-lived Rydberg states with finite pairwise interaction, a dark-state interference effect in the individual atoms, and spontaneous emission from their short-lived excited states lead to rapid, dissipative formation of an entangled steady state. We show that for a wide range of physical parameters, this entangled state is formed on a time scale given by the strengths of coherent Raman and Rabi fields applied to the atoms, while it is only weakly dependent on the Rydberg interaction strength.
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Affiliation(s)
- D D Bhaktavatsala Rao
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK 8000 Aarhus C, Denmark
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