1
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Bhattacharyya S, Bhattacharyya S. Demonstration of the Holonomically Controlled Non-Abelian Geometric Phase in a Three-Qubit System of a Nitrogen Vacancy Center. ENTROPY (BASEL, SWITZERLAND) 2022; 24:1593. [PMID: 36359682 PMCID: PMC9689909 DOI: 10.3390/e24111593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 10/24/2022] [Accepted: 10/27/2022] [Indexed: 06/16/2023]
Abstract
The holonomic approach to controlling (nitrogen-vacancy) NV-center qubits provides an elegant way of theoretically devising universal quantum gates that operate on qubits via calculable microwave pulses. There is, however, a lack of simulated results from the theory of holonomic control of quantum registers with more than two qubits describing the transition between the dark states. Considering this, we have been experimenting with the IBM Quantum Experience technology to determine the capabilities of simulating holonomic control of NV-centers for three qubits describing an eight-level system that produces a non-Abelian geometric phase. The tunability of the geometric phase via the detuning frequency is demonstrated through the high fidelity (~85%) of three-qubit off-resonant holonomic gates over the on-resonant ones. The transition between the dark states shows the alignment of the gate's dark state with the qubit's initial state hence decoherence of the multi-qubit system is well-controlled through a π/3 rotation.
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2
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Zhou WJ, You JB, Xiong X, Lu YW, Ang LK, Liu JF, Wu L. Cavity spectral-hole-burning to boost coherence in plasmon-emitter strong coupling systems. NANOTECHNOLOGY 2022; 33:475001. [PMID: 35981513 DOI: 10.1088/1361-6528/ac8aa3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 08/17/2022] [Indexed: 06/15/2023]
Abstract
Significant decoherence of the plasmon-emitter (i.e., plexcitonic) strong coupling systems hinders the progress towards their applications in quantum technology due to the unavoidable lossy nature of the plasmons. Inspired by the concept of spectral-hole-burning (SHB) for frequency-selective bleaching of the emitter ensemble, we propose 'cavity SHB' by introducing cavity modes with moderate quality factors to the plexcitonic system to boost its coherence. We show that the detuning of the introduced cavity mode with respect to the original plexcitonic system, which defines the location of the cavity SHB, is the most critical parameter. Simultaneously introducing two cavity modes of opposite detunings, the excited-state population of the emitter can be enhanced by 4.5 orders of magnitude within 300 fs, and the attenuation of the emitter's population can be slowed down by about 56 times. This theoretical proposal provides a new approach of cavity engineering to enhance the plasmon-emitter strong coupling systems' coherence, which is important for realistic hybrid-cavity design for applications in quantum technology.
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Affiliation(s)
- Wen-Jie Zhou
- Science, Mathematics and Technology (SMT), Singapore University of Technology and Design (SUTD), 8 Somapah Road, Singapore 487372, Singapore
| | - Jia-Bin You
- Institute of High Performance Computing, Agency for Science, Technology, and Research (A*STAR), 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Singapore
| | - Xiao Xiong
- Institute of High Performance Computing, Agency for Science, Technology, and Research (A*STAR), 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Singapore
| | - Yu-Wei Lu
- School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528000, People's Republic of China
| | - Lay Kee Ang
- Science, Mathematics and Technology (SMT), Singapore University of Technology and Design (SUTD), 8 Somapah Road, Singapore 487372, Singapore
| | - Jing-Feng Liu
- College of Electronic Engineering, South China Agricultural University, Guangzhou 510642, People's Republic of China
| | - Lin Wu
- Science, Mathematics and Technology (SMT), Singapore University of Technology and Design (SUTD), 8 Somapah Road, Singapore 487372, Singapore
- Institute of High Performance Computing, Agency for Science, Technology, and Research (A*STAR), 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Singapore
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3
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Matsuzaki Y, Imoto T, Susa Y. Generation of multipartite entanglement between spin-1 particles with bifurcation-based quantum annealing. Sci Rep 2022; 12:14964. [PMID: 36056092 PMCID: PMC9440094 DOI: 10.1038/s41598-022-17621-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 07/28/2022] [Indexed: 11/09/2022] Open
Abstract
Quantum annealing is a way to solve a combinational optimization problem where quantum fluctuation is induced by transverse fields. Recently, a bifurcation-based quantum annealing with spin-1 particles was suggested as another mechanism to implement the quantum annealing. In the bifurcation-based quantum annealing, each spin is initially prepared in [Formula: see text], let this state evolve by a time-dependent Hamiltonian in an adiabatic way, and we find a state spanned by [Formula: see text] at the end of the evolution. Here, we propose a scheme to generate multipartite entanglement, namely GHZ states, between spin-1 particles by using the bifurcation-based quantum annealing. We gradually decrease the detuning of the spin-1 particles while we adiabatically change the amplitude of the external driving fields. Due to the dipole-dipole interactions between the spin-1 particles, we can prepare the GHZ state after performing this protocol. We discuss possible implementations of our scheme by using nitrogen vacancy centers in diamond.
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Affiliation(s)
- Yuichiro Matsuzaki
- Research Center for Emerging Computing Technologies, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki, 305-8568, Japan. .,NEC-AIST Quantum Technology Cooperative Research Laboratory, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8568, Japan.
| | - Takashi Imoto
- Research Center for Emerging Computing Technologies, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki, 305-8568, Japan
| | - Yuki Susa
- NEC-AIST Quantum Technology Cooperative Research Laboratory, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8568, Japan.,System Platform Research Laboratories, NEC Corporation, Kawasaki, Kanagawa, 211-8666, Japan
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4
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Projecting an ultra-strongly-coupled system in a non-energy-eigenbasis with a driven nonlinear resonator. Sci Rep 2020; 10:1751. [PMID: 32019941 PMCID: PMC7000414 DOI: 10.1038/s41598-019-56866-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 12/02/2019] [Indexed: 11/22/2022] Open
Abstract
We explore the problem of projecting the ground-state of an ultra-strong-coupled circuit-QED system into a non-energy-eigenstate. As a measurement apparatus we consider a nonlinear driven resonator. We find that the post-measurement state of the nonlinear resonator exhibits a large correlation with the post-measurement state of the ultra-strongly coupled system even when the coupling between measurement device and system is much smaller than the energy scales of the system itself. While the projection is imperfect, we argue that because of the strong nonlinear response of the resonator it works in a practical regime where a linear measurement apparatus would fail.
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5
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Yan L, Su S, Hou Q, Yang W, Feng M. Macroscopically distinct superposition in a spin ensemble coupled to superconducting flux-qubits. OPTICS EXPRESS 2019; 27:377-390. [PMID: 30696125 DOI: 10.1364/oe.27.000377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 11/28/2018] [Indexed: 06/09/2023]
Abstract
Large optical nonlinearities can create fancy physics, such as big Schrödinger-cat states and quadrature squeezing. We present the possibility to practically generate macroscopic Schrödinger-cat states, based on a giant Kerr nonlinearity, in a diamond nitrogen-vacancy ensemble interacting with two coupled flux-qubits. The nonlinearity comes from a four-level N-type configuration formed by two coupled flux-qubits under the appropriately driving fields. We discuss the experimental feasibility in the presence of system dissipations using current laboratory technology and our scheme can be easily extended to other ensemble systems.
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6
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Mittiga T, Hsieh S, Zu C, Kobrin B, Machado F, Bhattacharyya P, Rui NZ, Jarmola A, Choi S, Budker D, Yao NY. Imaging the Local Charge Environment of Nitrogen-Vacancy Centers in Diamond. PHYSICAL REVIEW LETTERS 2018; 121:246402. [PMID: 30608732 DOI: 10.1103/physrevlett.121.246402] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Indexed: 06/09/2023]
Abstract
Characterizing the local internal environment surrounding solid-state spin defects is crucial to harnessing them as nanoscale sensors of external fields. This is especially germane to the case of defect ensembles which can exhibit a complex interplay between interactions, internal fields, and lattice strain. Working with the nitrogen-vacancy (NV) center in diamond, we demonstrate that local electric fields dominate the magnetic resonance behavior of NV ensembles at a low magnetic field. We introduce a simple microscopic model that quantitatively captures the observed spectra for samples with NV concentrations spanning more than two orders of magnitude. Motivated by this understanding, we propose and implement a novel method for the nanoscale localization of individual charges within the diamond lattice; our approach relies upon the fact that the charge induces a NV dark state which depends on the electric field orientation.
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Affiliation(s)
- T Mittiga
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - S Hsieh
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - C Zu
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - B Kobrin
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - F Machado
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - P Bhattacharyya
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - N Z Rui
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - A Jarmola
- Department of Physics, University of California, Berkeley, California 94720, USA
- U.S. Army Research Laboratory, Adelphi, Maryland 20783, USA
| | - S Choi
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - D Budker
- Department of Physics, University of California, Berkeley, California 94720, USA
- Helmholtz Institut, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - N Y Yao
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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7
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Ohta R, Okamoto H, Tawara T, Gotoh H, Yamaguchi H. Dynamic Control of the Coupling between Dark and Bright Excitons with Vibrational Strain. PHYSICAL REVIEW LETTERS 2018; 120:267401. [PMID: 30004772 DOI: 10.1103/physrevlett.120.267401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Indexed: 06/08/2023]
Abstract
We numerically and experimentally investigate strain-induced coupling between dark and bright excitons and its dynamic control using a gallium arsenide (GaAs) micromechanical resonator. Uniaxial strain induced by the mechanical resonance efficiently detunes the exciton energies and modulates the coupling strength via the deformation potential in GaAs. This allows optical access to the long-lived dark states without using any external electromagnetic field. This field-free approach could be expanded to a wide range of solid-state materials, leading to on-chip excitonic memories and circuits based on micromechanical resonators.
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Affiliation(s)
- Ryuichi Ohta
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi-shi, Kanagawa 243-0198, Japan
| | - Hajime Okamoto
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi-shi, Kanagawa 243-0198, Japan
| | - Takehiko Tawara
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi-shi, Kanagawa 243-0198, Japan
| | - Hideki Gotoh
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi-shi, Kanagawa 243-0198, Japan
| | - Hiroshi Yamaguchi
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi-shi, Kanagawa 243-0198, Japan
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8
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Lekavicius I, Golter DA, Oo T, Wang H. Transfer of Phase Information between Microwave and Optical Fields via an Electron Spin. PHYSICAL REVIEW LETTERS 2017; 119:063601. [PMID: 28949593 DOI: 10.1103/physrevlett.119.063601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Indexed: 06/07/2023]
Abstract
We demonstrate the coherent coupling and the resulting transfer of phase information between microwave and optical fields in a single nitrogen vacancy center in diamond. The relative phase of two microwave fields is encoded in a coherent superposition spin state. This phase information is then retrieved with a pair of optical fields. A related process is also used for the transfer of phase information from optical to microwave fields. These studies show the essential role of dark states, including optical pumping into the dark states, in the coherent microwave-optical coupling and open the door to the full quantum state transfer between microwave and optical fields in a solid-state spin ensemble.
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Affiliation(s)
- Ignas Lekavicius
- Department of Physics, University of Oregon, Eugene, Oregon 97403, USA
| | - D Andrew Golter
- Department of Physics, University of Oregon, Eugene, Oregon 97403, USA
| | - Thein Oo
- Department of Physics, University of Oregon, Eugene, Oregon 97403, USA
| | - Hailin Wang
- Department of Physics, University of Oregon, Eugene, Oregon 97403, USA
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9
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Kakuyanagi K, Matsuzaki Y, Déprez C, Toida H, Semba K, Yamaguchi H, Munro WJ, Saito S. Observation of Collective Coupling between an Engineered Ensemble of Macroscopic Artificial Atoms and a Superconducting Resonator. PHYSICAL REVIEW LETTERS 2016; 117:210503. [PMID: 27911564 DOI: 10.1103/physrevlett.117.210503] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Indexed: 06/06/2023]
Abstract
The hybridization of distinct quantum systems is now seen as an effective way to engineer the properties of an entire system leading to applications in quantum metamaterials, quantum simulation, and quantum metrology. Recent improvements in both fabrication techniques and qubit design have allowed the community to consider coupling large ensembles of artificial atoms, such as superconducting qubits, to a resonator. Here, we demonstrate the coherent coupling between a microwave resonator and a macroscopic ensemble composed of several thousand superconducting flux qubits, where we observe a large dispersive frequency shift in the spectrum of 250 MHz. We achieve the large dispersive shift with a collective enhancement of the coupling strength between the resonator and qubits. These results represent the largest number of coupled superconducting qubits realized so far.
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Affiliation(s)
- Kosuke Kakuyanagi
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan
| | - Yuichiro Matsuzaki
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan
| | - Corentin Déprez
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan
| | - Hiraku Toida
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan
| | - Kouichi Semba
- National Institute of Information and Communications Technology, 4-2-1, Nukuikitamachi, Koganei, Tokyo 184-8795, Japan
| | - Hiroshi Yamaguchi
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan
| | - William J Munro
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan
| | - Shiro Saito
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan
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10
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Keil M, Amit O, Zhou S, Groswasser D, Japha Y, Folman R. Fifteen years of cold matter on the atom chip: promise, realizations, and prospects. JOURNAL OF MODERN OPTICS 2016; 63:1840-1885. [PMID: 27499585 PMCID: PMC4960518 DOI: 10.1080/09500340.2016.1178820] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 03/22/2016] [Indexed: 05/30/2023]
Abstract
Here we review the field of atom chips in the context of Bose-Einstein Condensates (BEC) as well as cold matter in general. Twenty years after the first realization of the BEC and 15 years after the realization of the atom chip, the latter has been found to enable extraordinary feats: from producing BECs at a rate of several per second, through the realization of matter-wave interferometry, and all the way to novel probing of surfaces and new forces. In addition, technological applications are also being intensively pursued. This review will describe these developments and more, including new ideas which have not yet been realized.
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Affiliation(s)
- Mark Keil
- Department of Physics, Ben-Gurion University of the Negev, Be’er Sheva, Israel
| | - Omer Amit
- Department of Physics, Ben-Gurion University of the Negev, Be’er Sheva, Israel
| | - Shuyu Zhou
- Department of Physics, Ben-Gurion University of the Negev, Be’er Sheva, Israel
| | - David Groswasser
- Department of Physics, Ben-Gurion University of the Negev, Be’er Sheva, Israel
| | - Yonathan Japha
- Department of Physics, Ben-Gurion University of the Negev, Be’er Sheva, Israel
| | - Ron Folman
- Department of Physics, Ben-Gurion University of the Negev, Be’er Sheva, Israel
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11
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Song WL, Yang WL, Yin ZQ, Chen CY, Feng M. Controllable quantum dynamics of inhomogeneous nitrogen-vacancy center ensembles coupled to superconducting resonators. Sci Rep 2016; 6:33271. [PMID: 27627994 PMCID: PMC5024108 DOI: 10.1038/srep33271] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 08/22/2016] [Indexed: 11/09/2022] Open
Abstract
We explore controllable quantum dynamics of a hybrid system, which consists of an array of mutually coupled superconducting resonators (SRs) with each containing a nitrogen-vacancy center spin ensemble (NVE) in the presence of inhomogeneous broadening. We focus on a three-site model, which compared with the two-site case, shows more complicated and richer dynamical behavior, and displays a series of damped oscillations under various experimental situations, reflecting the intricate balance and competition between the NVE-SR collective coupling and the adjacent-site photon hopping. Particularly, we find that the inhomogeneous broadening of the spin ensemble can suppress the population transfer between the SR and the local NVE. In this context, although the inhomogeneous broadening of the spin ensemble diminishes entanglement among the NVEs, optimal entanglement, characterized by averaging the lower bound of concurrence, could be achieved through accurately adjusting the tunable parameters.
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Affiliation(s)
- Wan-Lu Song
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China.,University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Wan-Li Yang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Zhang-Qi Yin
- The Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, P. R. China
| | - Chang-Yong Chen
- Department of Physics, Shaoguan University, Shaoguan, Guangdong 512005, China
| | - Mang Feng
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
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12
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Coherence and multimode correlations from vacuum fluctuations in a microwave superconducting cavity. Nat Commun 2016; 7:12548. [PMID: 27562246 PMCID: PMC5007450 DOI: 10.1038/ncomms12548] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 07/11/2016] [Indexed: 11/23/2022] Open
Abstract
The existence of vacuum fluctuations is one of the most important predictions of modern quantum field theory. In the vacuum state, fluctuations occurring at different frequencies are uncorrelated. However, if a parameter in the Lagrangian of the field is modulated by an external pump, vacuum fluctuations stimulate spontaneous downconversion processes, creating squeezing between modes symmetric with respect to half of the frequency of the pump. Here we show that by double parametric pumping of a superconducting microwave cavity, it is possible to generate another type of correlation, namely coherence between photons in separate frequency modes. The coherence correlations are tunable by the phases of the pumps and are established by a quantum fluctuation that stimulates the simultaneous creation of two photon pairs. Our analysis indicates that the origin of this vacuum-induced coherence is the absence of which-way information in the frequency space. Vacuum fluctuations can produce observable phenomena which can potentially be harnessed, for example using the dynamical Casimir effect. Here, the authors show that, on the basis of the same effect, it is possible to establish distinct two-mode coherence correlations in a pumped microwave cavity owing to absence of which-way information.
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13
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Entanglement dynamics of Nitrogen-vacancy centers spin ensembles coupled to a superconducting resonator. Sci Rep 2016; 6:21775. [PMID: 26902910 PMCID: PMC4763275 DOI: 10.1038/srep21775] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 01/29/2016] [Indexed: 12/02/2022] Open
Abstract
Exploration of macroscopic quantum entanglement is of great interest in both fundamental science and practical application. We investigate a hybrid quantum system that consists of two nitrogen-vacancy centers ensembles (NVE) coupled to a superconducting coplanar waveguide resonator (CPWR). The collective magnetic coupling between the NVE and the CPWR is employed to generate macroscopic entanglement between the NVEs, where the CPWR acts as the quantum bus. We find that, this NVE-CPWR hybrid system behaves as a system of three coupled harmonic oscillators, and the excitation prepared initially in the CPWR can be distributed into these two NVEs. In the nondissipative case, the entanglement of NVEs oscillates periodically and the maximal entanglement always keeps unity if the CPWR is initially prepared in the odd coherent state. Considering the dissipative effect from the CPWR and NVEs, the amount of entanglement between these two NVEs strongly depends on the initial state of the CPWR, and the maximal entanglement can be tuned by adjusting the initial states of the total system. The experimental feasibility and challenge with currently available technology are discussed.
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14
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Zhang X, Zou CL, Zhu N, Marquardt F, Jiang L, Tang HX. Magnon dark modes and gradient memory. Nat Commun 2015; 6:8914. [PMID: 26568130 PMCID: PMC4660366 DOI: 10.1038/ncomms9914] [Citation(s) in RCA: 203] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 10/15/2015] [Indexed: 12/02/2022] Open
Abstract
Extensive efforts have been expended in developing hybrid quantum systems to overcome the short coherence time of superconducting circuits by introducing the naturally long-lived spin degree of freedom. Among all the possible materials, single-crystal yttrium iron garnet has shown up recently as a promising candidate for hybrid systems, and various highly coherent interactions, including strong and even ultrastrong coupling, have been demonstrated. One distinct advantage in these systems is that spins form well-defined magnon modes, which allows flexible and precise tuning. Here we demonstrate that by dissipation engineering, a non-Markovian interaction dynamics between the magnon and the microwave cavity photon can be achieved. Such a process enables us to build a magnon gradient memory to store information in the magnon dark modes, which decouple from the microwave cavity and thus preserve a long lifetime. Our findings provide a promising approach for developing long-lifetime, multimode quantum memories. Yttrium iron garnet is a ferrimagnetic insulator which demonstrates robust photon-spin coupling in hybrid microwave cavity systems. Here, the authors demonstrate a magnon gradient memory based on the dark modes of a strongly-coupled system of multiple yttrium iron garnet spheres.
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Affiliation(s)
- Xufeng Zhang
- Department of Electrical Engineering, Yale University, New Haven, Connecticut 06511, USA
| | - Chang-Ling Zou
- Department of Electrical Engineering, Yale University, New Haven, Connecticut 06511, USA.,Department of Applied Physics, Yale University, New Haven, Connecticut 06511, USA.,Key Lab of Quantum Information, University of Science and Technology of China, CAS, Hefei 230026, China
| | - Na Zhu
- Department of Electrical Engineering, Yale University, New Haven, Connecticut 06511, USA
| | - Florian Marquardt
- Institute for Theoretical Physics II, University of Erlangen-Nuremberg, Staudtstrasse 7, 91058 Erlangen, Germany.,Max Planck Institute for the Science of Light, Günther-Scharowsky-Straße 1/Bau 24, 91058 Erlangen, Germany
| | - Liang Jiang
- Department of Applied Physics, Yale University, New Haven, Connecticut 06511, USA
| | - Hong X Tang
- Department of Electrical Engineering, Yale University, New Haven, Connecticut 06511, USA
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15
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Cai H, Matsuzaki Y, Kakuyanagi K, Toida H, Zhu X, Mizuochi N, Nemoto K, Semba K, Munro WJ, Saito S, Yamaguchi H. Analysis of the spectroscopy of a hybrid system composed of a superconducting flux qubit and diamond NV(-) centers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:345702. [PMID: 26252646 DOI: 10.1088/0953-8984/27/34/345702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A hybrid system that combines the advantages of a superconductor flux qubit and an electron spin ensemble in diamond is one of the promising devices to realize quantum information processing. Exploring the properties of the superconductor diamond system is essential for the efficient use of this device. When we perform spectroscopy of this system, significant power broadening is observed. However, previous models to describe this system are known to be applicable only when the power broadening is negligible. Here, we construct a new approach to analyze this system with strong driving, and succeed in reproducing the spectrum with the power broadening. Our results provide an efficient way to analyze this hybrid system.
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Affiliation(s)
- H Cai
- NTT Basic Research Laboratories, NTT Corporation, Atsugi, Kanagawa 243-0198, Japan. Department of Physics, Tohoku University, Sendai, Miyagi 980-8578, Japan
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