1
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Jain S, Sägesser T, Hrmo P, Torkzaban C, Stadler M, Oswald R, Axline C, Bautista-Salvador A, Ospelkaus C, Kienzler D, Home J. Penning micro-trap for quantum computing. Nature 2024; 627:510-514. [PMID: 38480890 PMCID: PMC10954548 DOI: 10.1038/s41586-024-07111-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 01/24/2024] [Indexed: 03/18/2024]
Abstract
Trapped ions in radio-frequency traps are among the leading approaches for realizing quantum computers, because of high-fidelity quantum gates and long coherence times1-3. However, the use of radio-frequencies presents several challenges to scaling, including requiring compatibility of chips with high voltages4, managing power dissipation5 and restricting transport and placement of ions6. Here we realize a micro-fabricated Penning ion trap that removes these restrictions by replacing the radio-frequency field with a 3 T magnetic field. We demonstrate full quantum control of an ion in this setting, as well as the ability to transport the ion arbitrarily in the trapping plane above the chip. This unique feature of the Penning micro-trap approach opens up a modification of the quantum charge-coupled device architecture with improved connectivity and flexibility, facilitating the realization of large-scale trapped-ion quantum computing, quantum simulation and quantum sensing.
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Affiliation(s)
- Shreyans Jain
- Department of Physics, ETH Zürich, Zurich, Switzerland.
- Quantum Center, ETH Zürich, Zurich, Switzerland.
| | - Tobias Sägesser
- Department of Physics, ETH Zürich, Zurich, Switzerland
- Quantum Center, ETH Zürich, Zurich, Switzerland
| | - Pavel Hrmo
- Department of Physics, ETH Zürich, Zurich, Switzerland
- Quantum Center, ETH Zürich, Zurich, Switzerland
| | | | - Martin Stadler
- Department of Physics, ETH Zürich, Zurich, Switzerland
- Quantum Center, ETH Zürich, Zurich, Switzerland
| | - Robin Oswald
- Department of Physics, ETH Zürich, Zurich, Switzerland
- Quantum Center, ETH Zürich, Zurich, Switzerland
| | - Chris Axline
- Department of Physics, ETH Zürich, Zurich, Switzerland
| | - Amado Bautista-Salvador
- Institut für Quantenoptik, Leibniz Universität Hannover, Hannover, Germany
- Physikalisch-Technische Bundesanstalt, Braunschweig, Germany
| | - Christian Ospelkaus
- Institut für Quantenoptik, Leibniz Universität Hannover, Hannover, Germany
- Physikalisch-Technische Bundesanstalt, Braunschweig, Germany
| | - Daniel Kienzler
- Department of Physics, ETH Zürich, Zurich, Switzerland
- Quantum Center, ETH Zürich, Zurich, Switzerland
| | - Jonathan Home
- Department of Physics, ETH Zürich, Zurich, Switzerland
- Quantum Center, ETH Zürich, Zurich, Switzerland
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2
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Viotti L, Lombardo FC, Villar PI. Geometric Phase of a Transmon in a Dissipative Quantum Circuit. ENTROPY (BASEL, SWITZERLAND) 2024; 26:89. [PMID: 38275497 PMCID: PMC10814483 DOI: 10.3390/e26010089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Revised: 01/15/2024] [Accepted: 01/16/2024] [Indexed: 01/27/2024]
Abstract
Superconducting circuits reveal themselves as promising physical devices with multiple uses. Within those uses, the fundamental concept of the geometric phase accumulated by the state of a system shows up recurrently, as, for example, in the construction of geometric gates. Given this framework, we study the geometric phases acquired by a paradigmatic setup: a transmon coupled to a superconductor resonating cavity. We do so both for the case in which the evolution is unitary and when it is subjected to dissipative effects. These models offer a comprehensive quantum description of an anharmonic system interacting with a single mode of the electromagnetic field within a perfect or dissipative cavity, respectively. In the dissipative model, the non-unitary effects arise from dephasing, relaxation, and decay of the transmon coupled to its environment. Our approach enables a comparison of the geometric phases obtained in these models, leading to a thorough understanding of the corrections introduced by the presence of the environment.
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Affiliation(s)
- Ludmila Viotti
- The Abdus Salam International Center for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy
| | - Fernando C. Lombardo
- Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires 1428, Argentina
- Instituto de Física de Buenos Aires (IFIBA), CONICET—Universidad de Buenos Aires, Buenos Aires 1428, Argentina
| | - Paula I. Villar
- Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires 1428, Argentina
- Instituto de Física de Buenos Aires (IFIBA), CONICET—Universidad de Buenos Aires, Buenos Aires 1428, Argentina
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3
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Yu XD, Tong DM. Evolution Operator Can Always Be Separated into the Product of Holonomy and Dynamic Operators. PHYSICAL REVIEW LETTERS 2023; 131:200202. [PMID: 38039483 DOI: 10.1103/physrevlett.131.200202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 09/25/2023] [Accepted: 10/20/2023] [Indexed: 12/03/2023]
Abstract
The geometric phase is a fundamental quantity characterizing the holonomic feature of quantum systems. It is well known that the evolution operator of a quantum system undergoing a cyclic evolution can be simply written as the product of holonomic and dynamical components for the three special cases concerning the Berry phase, adiabatic non-Abelian geometric phase, and nonadiabatic Abelian geometric phase. However, for the most general case concerning the nonadiabatic non-Abelian geometric phase, how to separate the evolution operator into holonomic and dynamical components is a long-standing open problem. In this Letter, we solve this open problem. We show that the evolution operator of a quantum system can always be separated into the product of holonomy and dynamic operators. Based on it, we further derive a matrix representation of this separation formula for cyclic evolution, and give a necessary and sufficient condition for a general evolution being purely holonomic. Our finding is not only of theoretical interest itself, but also of vital importance for the application of quantum holonomy. It unifies the representations of all four types of evolution concerning the adiabatic/nonadiabatic Abelian/non-Abelian geometric phase, and provides a general approach to realizing purely holonomic evolution.
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Affiliation(s)
- Xiao-Dong Yu
- Department of Physics, Shandong University, Jinan 250100, China
| | - D M Tong
- Department of Physics, Shandong University, Jinan 250100, China
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4
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Hrmo P, Wilhelm B, Gerster L, van Mourik MW, Huber M, Blatt R, Schindler P, Monz T, Ringbauer M. Native qudit entanglement in a trapped ion quantum processor. Nat Commun 2023; 14:2242. [PMID: 37076475 PMCID: PMC10115791 DOI: 10.1038/s41467-023-37375-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 03/15/2023] [Indexed: 04/21/2023] Open
Abstract
Quantum information carriers, just like most physical systems, naturally occupy high-dimensional Hilbert spaces. Instead of restricting them to a two-level subspace, these high-dimensional (qudit) quantum systems are emerging as a powerful resource for the next generation of quantum processors. Yet harnessing the potential of these systems requires efficient ways of generating the desired interaction between them. Here, we experimentally demonstrate an implementation of a native two-qudit entangling gate up to dimension 5 in a trapped-ion system. This is achieved by generalizing a recently proposed light-shift gate mechanism to generate genuine qudit entanglement in a single application of the gate. The gate seamlessly adapts to the local dimension of the system with a calibration overhead that is independent of the dimension.
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Affiliation(s)
- Pavel Hrmo
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25/4, 6020, Innsbruck, Austria.
| | - Benjamin Wilhelm
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25/4, 6020, Innsbruck, Austria
| | - Lukas Gerster
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25/4, 6020, Innsbruck, Austria
| | - Martin W van Mourik
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25/4, 6020, Innsbruck, Austria
| | - Marcus Huber
- Atominstitut, Technische Universität Wien, 1020, Vienna, Austria
- Institute for Quantum Optics and Quantum Information-IQOQI Vienna, Austrian Academy of Sciences, Boltzmanngasse 3, 1090, Vienna, Austria
| | - Rainer Blatt
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25/4, 6020, Innsbruck, Austria
- Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Technikerstraße 21a, 6020, Innsbruck, Austria
- AQT, Technikerstraße 17, 6020, Innsbruck, Austria
| | - Philipp Schindler
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25/4, 6020, Innsbruck, Austria
| | - Thomas Monz
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25/4, 6020, Innsbruck, Austria
- AQT, Technikerstraße 17, 6020, Innsbruck, Austria
| | - Martin Ringbauer
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25/4, 6020, Innsbruck, Austria
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5
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Tobalina A, Munuera-Javaloy C, Torrontegui E, Muga JG, Casanova J. Tailored ion beam for precise colour centre creation. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2022; 380:20210271. [PMID: 36335951 DOI: 10.1098/rsta.2021.0271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 09/09/2022] [Indexed: 06/16/2023]
Abstract
We present an invariant-based quantum control scheme leading to a highly monochromatic ion beam from a Paul trap. Our protocol is implementable by supplying the segmented electrodes in the trap with voltages of the order of volts. This mitigates the impact of fluctuations in previous designs and leads to a low-dispersion beam of ions. Moreover, our proposal does not rely on sympathetically cooling ions, which bypasses the need of loading different species in the trap-namely, the propelled ion and, e.g. a [Formula: see text] to exert sympathetic cooling-significantly incrementing the repetition rate of the launching procedure. Our scheme is based on an invariant operator linear in position and momentum, which enables us to control the average extraction energy and the outgoing momentum spread. In addition, we propose a sequential operation to tailor the transversal properties of the beam before the ejection to minimize the impact spot and to increase the lateral resolution of the implantation. This article is part of the theme issue 'Shortcuts to adiabaticity: theoretical, experimental and interdisciplinary perspectives'.
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Affiliation(s)
- A Tobalina
- Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, Bilbao 48080, Spain
- EHU Quantum Center, University of the Basque Country UPV/EHU, Leioa, Spain
| | - C Munuera-Javaloy
- Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, Bilbao 48080, Spain
- EHU Quantum Center, University of the Basque Country UPV/EHU, Leioa, Spain
| | - E Torrontegui
- Departamento de Física, Universidad Carlos III de Madrid, Avda. de la Universidad 30, Leganés 28911, Spain
- Instituto de Física Fundamental IFF-CSIC, Calle Serrano 113b, Madrid 28006, Spain
| | - J G Muga
- Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, Bilbao 48080, Spain
- EHU Quantum Center, University of the Basque Country UPV/EHU, Leioa, Spain
| | - J Casanova
- Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, Bilbao 48080, Spain
- EHU Quantum Center, University of the Basque Country UPV/EHU, Leioa, Spain
- IKERBASQUE, Basque Foundation for Science, Plaza Euskadi 5, Bilbao 48009, Spain
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6
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Fang C, Wang Y, Huang S, Brown KR, Kim J. Crosstalk Suppression in Individually Addressed Two-Qubit Gates in a Trapped-Ion Quantum Computer. PHYSICAL REVIEW LETTERS 2022; 129:240504. [PMID: 36563266 DOI: 10.1103/physrevlett.129.240504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 11/16/2022] [Indexed: 06/17/2023]
Abstract
Crosstalk between target and neighboring spectator qubits due to spillover of control signals represents a major error source limiting the fidelity of two-qubit entangling gates in quantum computers. We show that in our laser-driven trapped-ion system coherent crosstalk error can be modeled as residual Xσ[over ^]_{ϕ} interaction and can be actively canceled by single-qubit echoing pulses. We propose and demonstrate a crosstalk suppression scheme that eliminates all first-order crosstalk utilizing only local control of target qubits, as opposed to an existing scheme which requires control over all neighboring qubits. We report a two-qubit Bell state fidelity of 99.52(6)% with the echoing pulses applied after collective gates and 99.37(5)% with the echoing pulses applied to each gate in a five-ion chain. This scheme is widely applicable to other platforms with analogous interaction Hamiltonians.
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Affiliation(s)
- Chao Fang
- Duke Quantum Center, Duke University, Durham, North Carolina 27701, USA
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Ye Wang
- Duke Quantum Center, Duke University, Durham, North Carolina 27701, USA
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Shilin Huang
- Duke Quantum Center, Duke University, Durham, North Carolina 27701, USA
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Kenneth R Brown
- Duke Quantum Center, Duke University, Durham, North Carolina 27701, USA
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
| | - Jungsang Kim
- Duke Quantum Center, Duke University, Durham, North Carolina 27701, USA
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
- IonQ, Inc., College Park, Maryland 20740, USA
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7
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Li BW, Mei QX, Wu YK, Cai ML, Wang Y, Yao L, Zhou ZC, Duan LM. Observation of Non-Markovian Spin Dynamics in a Jaynes-Cummings-Hubbard Model Using a Trapped-Ion Quantum Simulator. PHYSICAL REVIEW LETTERS 2022; 129:140501. [PMID: 36240415 DOI: 10.1103/physrevlett.129.140501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 09/13/2022] [Indexed: 06/16/2023]
Abstract
The Jaynes-Cummings-Hubbard (JCH) model is a fundamental many-body model for light-matter interaction. As a leading platform for quantum simulation, the trapped ion system has realized the JCH model for two to three ions. Here, we report the quantum simulation of the JCH model using up to 32 ions. We verify the simulation results even for large ion numbers by engineering low excitations and thus low effective dimensions; then we extend to 32 excitations for an effective dimension of 2^{77}, which is difficult for classical computers. By regarding the phonon modes as baths, we explore Markovian or non-Markovian spin dynamics in different parameter regimes of the JCH model, similar to quantum emitters in a structured photonic environment. We further examine the dependence of the non-Markovian dynamics on the effective Hilbert space dimension. Our Letter demonstrates the trapped ion system as a powerful quantum simulator for many-body physics and open quantum systems.
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Affiliation(s)
- B-W Li
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, People's Republic of China
| | - Q-X Mei
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, People's Republic of China
| | - Y-K Wu
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, People's Republic of China
| | - M-L Cai
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, People's Republic of China
- HYQ Co., Ltd., Beijing, 100176, People's Republic of China
| | - Y Wang
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, People's Republic of China
| | - L Yao
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, People's Republic of China
- HYQ Co., Ltd., Beijing, 100176, People's Republic of China
| | - Z-C Zhou
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, People's Republic of China
| | - L-M Duan
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, People's Republic of China
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8
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Quantum Optimal Control: Practical Aspects and Diverse Methods. J Indian Inst Sci 2022. [DOI: 10.1007/s41745-022-00311-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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9
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Müller MM, Said RS, Jelezko F, Calarco T, Montangero S. One decade of quantum optimal control in the chopped random basis. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2022; 85:076001. [PMID: 35605567 DOI: 10.1088/1361-6633/ac723c] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 05/23/2022] [Indexed: 06/15/2023]
Abstract
The chopped random basis (CRAB) ansatz for quantum optimal control has been proven to be a versatile tool to enable quantum technology applications such as quantum computing, quantum simulation, quantum sensing, and quantum communication. Its capability to encompass experimental constraints-while maintaining an access to the usually trap-free control landscape-and to switch from open-loop to closed-loop optimization (including with remote access-or RedCRAB) is contributing to the development of quantum technology on many different physical platforms. In this review article we present the development, the theoretical basis and the toolbox for this optimization algorithm, as well as an overview of the broad range of different theoretical and experimental applications that exploit this powerful technique.
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Affiliation(s)
- Matthias M Müller
- Peter Grünberg Institute-Quantum Control (PGI-8), Forschungszentrum Jülich GmbH, D-52425 Germany
| | - Ressa S Said
- Institute for Quantum Optics & Center for Integrated Quantum Science and Technology, Universität Ulm, D-89081 Germany
| | - Fedor Jelezko
- Institute for Quantum Optics & Center for Integrated Quantum Science and Technology, Universität Ulm, D-89081 Germany
| | - Tommaso Calarco
- Peter Grünberg Institute-Quantum Control (PGI-8), Forschungszentrum Jülich GmbH, D-52425 Germany
- Institute for Theoretical Physics, University of Cologne, D-50937 Germany
| | - Simone Montangero
- Dipartimento di Fisica e Astronomia 'G. Galilei', Università degli Studi di Padova & INFN, Sezione di Padova, I-35131 Italy
- Padua Quantum Technology Center, Università degli Studi di Padova, I-35131 Italy
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10
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Xu K, Zhang YR, Sun ZH, Li H, Song P, Xiang Z, Huang K, Li H, Shi YH, Chen CT, Song X, Zheng D, Nori F, Wang H, Fan H. Metrological Characterization of Non-Gaussian Entangled States of Superconducting Qubits. PHYSICAL REVIEW LETTERS 2022; 128:150501. [PMID: 35499907 DOI: 10.1103/physrevlett.128.150501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 03/15/2022] [Indexed: 06/14/2023]
Abstract
Multipartite entangled states are significant resources for both quantum information processing and quantum metrology. In particular, non-Gaussian entangled states are predicted to achieve a higher sensitivity of precision measurements than Gaussian states. On the basis of metrological sensitivity, the conventional linear Ramsey squeezing parameter (RSP) efficiently characterizes the Gaussian entangled atomic states but fails for much wider classes of highly sensitive non-Gaussian states. These complex non-Gaussian entangled states can be classified by the nonlinear squeezing parameter (NLSP), as a generalization of the RSP with respect to nonlinear observables and identified via the Fisher information. However, the NLSP has never been measured experimentally. Using a 19-qubit programmable superconducting processor, we report the characterization of multiparticle entangled states generated during its nonlinear dynamics. First, selecting ten qubits, we measure the RSP and the NLSP by single-shot readouts of collective spin operators in several different directions. Then, by extracting the Fisher information of the time-evolved state of all 19 qubits, we observe a large metrological gain of 9.89_{-0.29}^{+0.28} dB over the standard quantum limit, indicating a high level of multiparticle entanglement for quantum-enhanced phase sensitivity. Benefiting from high-fidelity full controls and addressable single-shot readouts, the superconducting processor with interconnected qubits provides an ideal platform for engineering and benchmarking non-Gaussian entangled states that are useful for quantum-enhanced metrology.
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Affiliation(s)
- Kai Xu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yu-Ran Zhang
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
- RIKEN Center for Quantum Computing (RQC), Wako-shi, Saitama 351-0198, Japan
| | - Zheng-Hang Sun
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Hekang Li
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Pengtao Song
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Zhongcheng Xiang
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Kaixuan Huang
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Hao Li
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yun-Hao Shi
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Chi-Tong Chen
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiaohui Song
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Dongning Zheng
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Franco Nori
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
- RIKEN Center for Quantum Computing (RQC), Wako-shi, Saitama 351-0198, Japan
- Physics Department, University of Michigan, Ann Arbor, Michigan 48109-1040, USA
| | - H Wang
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Heng Fan
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Beijing Academy of Quantum Information Sciences and CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
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11
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Pijn D, Onishchenko O, Hilder J, Poschinger UG, Schmidt-Kaler F, Uzdin R. Detecting Heat Leaks with Trapped Ion Qubits. PHYSICAL REVIEW LETTERS 2022; 128:110601. [PMID: 35363006 DOI: 10.1103/physrevlett.128.110601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 01/18/2022] [Accepted: 02/08/2022] [Indexed: 06/14/2023]
Abstract
The concept of passivity has been conceived to set bounds on the evolution of microscopic systems initialized in thermal states. We experimentally demonstrate the utility of two frameworks, global passivity and passivity deformation, for the detection of coupling to a hidden environment. We employ a trapped-ion quantum processor, where system qubits undergoing unitary evolution may optionally be coupled to an unobserved environment qubit, resulting in a heat leak. Evaluating the measurement data from the system qubits only, we show that global passivity can verify the presence of a heat leak, which is not detectable by a microscopic equivalent of the second law of thermodynamics. Furthermore, we experimentally show that passivity deformation allows for even more sensitive detection of heat leaks, as compared to global passivity, and detect a heat leak with an error margin of 5.3 standard deviations, in a scenario where other tests fail.
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Affiliation(s)
- D Pijn
- Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany
| | - O Onishchenko
- Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany
| | - J Hilder
- Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany
| | - U G Poschinger
- Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany
| | - F Schmidt-Kaler
- Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany
| | - R Uzdin
- Fritz Haber Research Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
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12
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Tinkey HN, Clark CR, Sawyer BC, Brown KR. Transport-Enabled Entangling Gate for Trapped Ions. PHYSICAL REVIEW LETTERS 2022; 128:050502. [PMID: 35179924 DOI: 10.1103/physrevlett.128.050502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 01/07/2022] [Indexed: 06/14/2023]
Abstract
We implement a 2-qubit entangling Mølmer-Sørensen interaction by transporting two cotrapped ^{40}Ca^{+} ions through a stationary, bichromatic optical beam within a surface-electrode Paul trap. We describe a procedure for achieving a constant Doppler shift during the transport, which uses fine temporal adjustment of the moving confinement potential. The fixed interaction duration of the ions transported through the laser beam as well as the dynamically changing ac Stark shift require alterations to the calibration procedures used for a stationary gate. We use the interaction to produce Bell states with fidelities commensurate to those of stationary gates performed in the same system. This result establishes the feasibility of actively incorporating ion transport into quantum information entangling operations.
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Affiliation(s)
- Holly N Tinkey
- Georgia Tech Research Institute, Atlanta, Georgia 30332, USA
| | - Craig R Clark
- Georgia Tech Research Institute, Atlanta, Georgia 30332, USA
| | - Brian C Sawyer
- Georgia Tech Research Institute, Atlanta, Georgia 30332, USA
| | - Kenton R Brown
- Georgia Tech Research Institute, Atlanta, Georgia 30332, USA
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13
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Mazzanti M, Schüssler RX, Arias Espinoza JD, Wu Z, Gerritsma R, Safavi-Naini A. Trapped Ion Quantum Computing Using Optical Tweezers and Electric Fields. PHYSICAL REVIEW LETTERS 2021; 127:260502. [PMID: 35029474 DOI: 10.1103/physrevlett.127.260502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 11/09/2021] [Indexed: 06/14/2023]
Abstract
We propose a new scalable architecture for trapped ion quantum computing that combines optical tweezers delivering qubit state-dependent local potentials with oscillating electric fields. Since the electric field allows for long-range qubit-qubit interactions mediated by the center-of-mass motion of the ion crystal alone, it is inherently scalable to large ion crystals. Furthermore, our proposed scheme does not rely on either ground-state cooling or the Lamb-Dicke approximation. We study the effects of imperfect cooling of the ion crystal, as well as the role of unwanted qubit-motion entanglement, and discuss the prospects of implementing the state-dependent tweezers in the laboratory.
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Affiliation(s)
- M Mazzanti
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, 1098 XH Amsterdam, Netherlands
| | - R X Schüssler
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, 1098 XH Amsterdam, Netherlands
| | - J D Arias Espinoza
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, 1098 XH Amsterdam, Netherlands
| | - Z Wu
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, 1098 XH Amsterdam, Netherlands
| | - R Gerritsma
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, 1098 XH Amsterdam, Netherlands
- QuSoft, Science Park 123, 1098 XG Amsterdam, Netherlands
| | - A Safavi-Naini
- QuSoft, Science Park 123, 1098 XG Amsterdam, Netherlands
- Institute for Theoretical Physics, Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, Netherlands
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14
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Coherence Trapping in Open Two-Qubit Dynamics. Symmetry (Basel) 2021. [DOI: 10.3390/sym13122445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
In this manuscript, we examine the dynamical behavior of the coherence in open quantum systems using the l1 norm. We consider a two-qubit system that evolves in the framework of Kossakowski-type quantum dynamical semigroups (KTQDSs) of completely positive maps (CPMs). We find that the quantum coherence can be asymptotically maintained with respect to the values of the system parameters. Moreover, we show that the quantum coherence can resist the effect of the environment and preserve even in the regime of long times. The obtained results also show that the initially separable states can provide a finite value of the coherence during the time evolution. Because of such properties, several states in this type of environments are good candidates for incorporating quantum information and optics (QIO) schemes. Finally, we compare the dynamical behavior of the coherence with the entire quantum correlation.
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15
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Clark CR, Tinkey HN, Sawyer BC, Meier AM, Burkhardt KA, Seck CM, Shappert CM, Guise ND, Volin CE, Fallek SD, Hayden HT, Rellergert WG, Brown KR. High-Fidelity Bell-State Preparation with ^{40}Ca^{+} Optical Qubits. PHYSICAL REVIEW LETTERS 2021; 127:130505. [PMID: 34623832 DOI: 10.1103/physrevlett.127.130505] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 08/19/2021] [Indexed: 05/02/2023]
Abstract
Entanglement generation in trapped-ion systems has relied thus far on two distinct but related geometric phase gate techniques: Mølmer-Sørensen and light-shift gates. We recently proposed a variant of the light-shift scheme where the qubit levels are separated by an optical frequency [B. C. Sawyer and K. R. Brown, Phys. Rev. A 103, 022427 (2021)PLRAAN2469-992610.1103/PhysRevA.103.022427]. Here we report an experimental demonstration of this entangling gate using a pair of ^{40}Ca^{+} ions in a cryogenic surface-electrode ion trap and a commercial, high-power, 532 nm Nd:YAG laser. Generating a Bell state in 35 μs, we directly measure an infidelity of 6(3)×10^{-4} without subtraction of experimental errors. The 532 nm gate laser wavelength suppresses intrinsic photon scattering error to ∼1×10^{-5}.
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Affiliation(s)
- Craig R Clark
- Georgia Tech Research Institute, Atlanta, Georgia 30332, USA
| | - Holly N Tinkey
- Georgia Tech Research Institute, Atlanta, Georgia 30332, USA
| | - Brian C Sawyer
- Georgia Tech Research Institute, Atlanta, Georgia 30332, USA
| | - Adam M Meier
- Georgia Tech Research Institute, Atlanta, Georgia 30332, USA
| | | | | | | | | | - Curtis E Volin
- Georgia Tech Research Institute, Atlanta, Georgia 30332, USA
| | | | - Harley T Hayden
- Georgia Tech Research Institute, Atlanta, Georgia 30332, USA
| | | | - Kenton R Brown
- Georgia Tech Research Institute, Atlanta, Georgia 30332, USA
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16
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Hai K, Wang Y, Chen Q, Hai W. Transparent qubit manipulations with spin-orbit coupled two-electron nanowire quantum dot. Sci Rep 2021; 11:18839. [PMID: 34552131 PMCID: PMC8458319 DOI: 10.1038/s41598-021-98152-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 09/01/2021] [Indexed: 11/12/2022] Open
Abstract
We report on the first set of exact orthonormalized states to an ac driven one-dimensional (1D) two-electron nanowire quantum dot with the Rashba-Dresselhaus coexisted spin-orbit coupling (SOC) and the controlled magnetic field orientation and trapping frequency. In the ground state case, it is shown that the spatiotemporal evolutions of probability densities occupying internal spin states and the transfer rates between different spin states can be adjusted by the ac electric field and the intensities of SOC and magnetic field. Effects of the system parameters and initial-state-dependent constants on the mean entanglement are revealed, where the approximately maximal entanglement associated with the stronger SOC and its insensitivity to the initial and parametric perturbations are demonstrated numerically. A novel resonance transition mechanism is found, in which the ladder-like time-evolution process of expected energy and the transition time between two arbitrary exact states are controlled by the ac field strength. Using such maximally entangled exact states to encode qubits can render the qubit control more transparent and robust. The results could be extended to 2D case and to an array of two-electron quantum dots with weak neighboring coupling for quantum information processing.
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Affiliation(s)
- Kuo Hai
- Department of Physics and Key Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of Education, Hunan Normal University, Changsha, 410081, China.
| | - Yifan Wang
- Department of Physics and Key Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of Education, Hunan Normal University, Changsha, 410081, China
| | - Qiong Chen
- Department of Physics and Key Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of Education, Hunan Normal University, Changsha, 410081, China
| | - Wenhua Hai
- Department of Physics and Key Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of Education, Hunan Normal University, Changsha, 410081, China.
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17
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Srinivas R, Burd SC, Knaack HM, Sutherland RT, Kwiatkowski A, Glancy S, Knill E, Wineland DJ, Leibfried D, Wilson AC, Allcock DTC, Slichter DH. High-fidelity laser-free universal control of trapped ion qubits. Nature 2021; 597:209-213. [PMID: 34497396 DOI: 10.1038/s41586-021-03809-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 07/07/2021] [Indexed: 11/09/2022]
Abstract
Universal control of multiple qubits-the ability to entangle qubits and to perform arbitrary individual qubit operations1-is a fundamental resource for quantum computing2, simulation3 and networking4. Qubits realized in trapped atomic ions have shown the highest-fidelity two-qubit entangling operations5-7 and single-qubit rotations8 so far. Universal control of trapped ion qubits has been separately demonstrated using tightly focused laser beams9-12 or by moving ions with respect to laser beams13-15, but at lower fidelities. Laser-free entangling methods16-20 may offer improved scalability by harnessing microwave technology developed for wireless communications, but so far their performance has lagged the best reported laser-based approaches. Here we demonstrate high-fidelity laser-free universal control of two trapped-ion qubits by creating both symmetric and antisymmetric maximally entangled states with fidelities of [Formula: see text] and [Formula: see text], respectively (68 per cent confidence level), corrected for initialization error. We use a scheme based on radiofrequency magnetic field gradients combined with microwave magnetic fields that is robust against multiple sources of decoherence and usable with essentially any trapped ion species. The scheme has the potential to perform simultaneous entangling operations on multiple pairs of ions in a large-scale trapped-ion quantum processor without increasing control signal power or complexity. Combining this technology with low-power laser light delivered via trap-integrated photonics21,22 and trap-integrated photon detectors for qubit readout23,24 provides an opportunity for scalable, high-fidelity, fully chip-integrated trapped-ion quantum computing.
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Affiliation(s)
- R Srinivas
- National Institute of Standards and Technology, Boulder, CO, USA. .,Department of Physics, University of Colorado, Boulder, CO, USA. .,Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, UK.
| | - S C Burd
- National Institute of Standards and Technology, Boulder, CO, USA.,Department of Physics, University of Colorado, Boulder, CO, USA.,Department of Physics, Stanford University, Stanford, CA, USA
| | - H M Knaack
- National Institute of Standards and Technology, Boulder, CO, USA.,Department of Physics, University of Colorado, Boulder, CO, USA
| | - R T Sutherland
- Physics Division, Physical and Life Sciences, Lawrence Livermore National Laboratory, Livermore, CA, USA.,Department of Electrical and Computer Engineering, University of Texas at San Antonio, San Antonio, TX, USA.,Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX, USA
| | - A Kwiatkowski
- National Institute of Standards and Technology, Boulder, CO, USA.,Department of Physics, University of Colorado, Boulder, CO, USA
| | - S Glancy
- National Institute of Standards and Technology, Boulder, CO, USA
| | - E Knill
- National Institute of Standards and Technology, Boulder, CO, USA.,Center for Theory of Quantum Matter, University of Colorado, Boulder, CO, USA
| | - D J Wineland
- National Institute of Standards and Technology, Boulder, CO, USA.,Department of Physics, University of Colorado, Boulder, CO, USA.,Department of Physics, University of Oregon, Eugene, OR, USA
| | - D Leibfried
- National Institute of Standards and Technology, Boulder, CO, USA
| | - A C Wilson
- National Institute of Standards and Technology, Boulder, CO, USA
| | - D T C Allcock
- National Institute of Standards and Technology, Boulder, CO, USA.,Department of Physics, University of Colorado, Boulder, CO, USA.,Department of Physics, University of Oregon, Eugene, OR, USA
| | - D H Slichter
- National Institute of Standards and Technology, Boulder, CO, USA.
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18
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Gilmore KA, Affolter M, Lewis-Swan RJ, Barberena D, Jordan E, Rey AM, Bollinger JJ. Quantum-enhanced sensing of displacements and electric fields with two-dimensional trapped-ion crystals. Science 2021; 373:673-678. [PMID: 34353950 DOI: 10.1126/science.abi5226] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 06/25/2021] [Indexed: 11/02/2022]
Abstract
Fully controllable ultracold atomic systems are creating opportunities for quantum sensing, yet demonstrating a quantum advantage in useful applications by harnessing entanglement remains a challenging task. Here, we realize a many-body quantum-enhanced sensor to detect displacements and electric fields using a crystal of ~150 trapped ions. The center-of-mass vibrational mode of the crystal serves as a high-Q mechanical oscillator, and the collective electronic spin serves as the measurement device. By entangling the oscillator and collective spin and controlling the coherent dynamics via a many-body echo, a displacement is mapped into a spin rotation while avoiding quantum back-action and thermal noise. We achieve a sensitivity to displacements of 8.8 ± 0.4 decibels below the standard quantum limit and a sensitivity for measuring electric fields of 240 ± 10 nanovolts per meter in 1 second. Feasible improvements should enable the use of trapped ions in searches for dark matter.
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Affiliation(s)
- Kevin A Gilmore
- Center for Theory of Quantum Matter, University of Colorado, Boulder, CO 80309, USA. .,Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019, USA.,National Institute of Standards and Technology, Boulder, CO 80305, USA.,Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Matthew Affolter
- Center for Theory of Quantum Matter, University of Colorado, Boulder, CO 80309, USA.,National Institute of Standards and Technology, Boulder, CO 80305, USA
| | - Robert J Lewis-Swan
- National Institute of Standards and Technology, Boulder, CO 80305, USA.,Department of Physics, University of Colorado, Boulder, CO 80309, USA.,Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019, USA.,Center for Quantum Research and Technology, University of Oklahoma, Norman, OK 73019, USA
| | - Diego Barberena
- Center for Quantum Research and Technology, University of Oklahoma, Norman, OK 73019, USA.,JILA, NIST, and Department of Physics, University of Colorado, Boulder, CO 80309, USA.,JILA, NIST, and Department of Physics, University of Colorado, Boulder, CO 80309, USA.,Center for Theory of Quantum Matter, University of Colorado, Boulder, CO 80309, USA
| | - Elena Jordan
- Center for Theory of Quantum Matter, University of Colorado, Boulder, CO 80309, USA.,National Institute of Standards and Technology, Boulder, CO 80305, USA
| | - Ana Maria Rey
- Center for Quantum Research and Technology, University of Oklahoma, Norman, OK 73019, USA. .,JILA, NIST, and Department of Physics, University of Colorado, Boulder, CO 80309, USA.,JILA, NIST, and Department of Physics, University of Colorado, Boulder, CO 80309, USA.,Center for Theory of Quantum Matter, University of Colorado, Boulder, CO 80309, USA
| | - John J Bollinger
- Center for Theory of Quantum Matter, University of Colorado, Boulder, CO 80309, USA. .,National Institute of Standards and Technology, Boulder, CO 80305, USA
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19
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MacDonell RJ, Dickerson CE, Birch CJT, Kumar A, Edmunds CL, Biercuk MJ, Hempel C, Kassal I. Analog quantum simulation of chemical dynamics. Chem Sci 2021; 12:9794-9805. [PMID: 34349953 PMCID: PMC8293981 DOI: 10.1039/d1sc02142g] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 06/14/2021] [Indexed: 11/21/2022] Open
Abstract
Ultrafast chemical reactions are difficult to simulate because they involve entangled, many-body wavefunctions whose computational complexity grows rapidly with molecular size. In photochemistry, the breakdown of the Born-Oppenheimer approximation further complicates the problem by entangling nuclear and electronic degrees of freedom. Here, we show that analog quantum simulators can efficiently simulate molecular dynamics using commonly available bosonic modes to represent molecular vibrations. Our approach can be implemented in any device with a qudit controllably coupled to bosonic oscillators and with quantum hardware resources that scale linearly with molecular size, and offers significant resource savings compared to digital quantum simulation algorithms. Advantages of our approach include a time resolution orders of magnitude better than ultrafast spectroscopy, the ability to simulate large molecules with limited hardware using a Suzuki-Trotter expansion, and the ability to implement realistic system-bath interactions with only one additional interaction per mode. Our approach can be implemented with current technology; e.g., the conical intersection in pyrazine can be simulated using a single trapped ion. Therefore, we expect our method will enable classically intractable chemical dynamics simulations in the near term.
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Affiliation(s)
- Ryan J MacDonell
- School of Chemistry, University of Sydney NSW 2006 Australia
- University of Sydney Nano Institute, University of Sydney NSW 2006 Australia
| | - Claire E Dickerson
- School of Chemistry, University of Sydney NSW 2006 Australia
- School of Physics, University of Sydney NSW 2006 Australia
- ARC Centre of Excellence for Engineered Quantum Systems, University of Sydney NSW 2006 Australia
- University of Sydney Nano Institute, University of Sydney NSW 2006 Australia
| | - Clare J T Birch
- School of Chemistry, University of Sydney NSW 2006 Australia
- University of Sydney Nano Institute, University of Sydney NSW 2006 Australia
| | - Alok Kumar
- Department of Chemistry, Indian Institute of Technology Bombay Mumbai 400076 India
| | - Claire L Edmunds
- School of Physics, University of Sydney NSW 2006 Australia
- ARC Centre of Excellence for Engineered Quantum Systems, University of Sydney NSW 2006 Australia
| | - Michael J Biercuk
- School of Physics, University of Sydney NSW 2006 Australia
- ARC Centre of Excellence for Engineered Quantum Systems, University of Sydney NSW 2006 Australia
| | - Cornelius Hempel
- School of Physics, University of Sydney NSW 2006 Australia
- ARC Centre of Excellence for Engineered Quantum Systems, University of Sydney NSW 2006 Australia
- University of Sydney Nano Institute, University of Sydney NSW 2006 Australia
| | - Ivan Kassal
- School of Chemistry, University of Sydney NSW 2006 Australia
- University of Sydney Nano Institute, University of Sydney NSW 2006 Australia
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20
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Milne AR, Hempel C, Li L, Edmunds CL, Slatyer HJ, Ball H, Hush MR, Biercuk MJ. Quantum Oscillator Noise Spectroscopy via Displaced Cat States. PHYSICAL REVIEW LETTERS 2021; 126:250506. [PMID: 34241523 DOI: 10.1103/physrevlett.126.250506] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 04/21/2021] [Indexed: 06/13/2023]
Abstract
Quantum harmonic oscillators are central to many modern quantum technologies. We introduce a method to determine the frequency noise spectrum of oscillator modes through coupling them to a qubit with continuously driven qubit-state-dependent displacements. We reconstruct the noise spectrum using a series of different drive phase and amplitude modulation patterns in conjunction with a data-fusion routine based on convex optimization. We apply the technique to the identification of intrinsic noise in the motional frequency of a single trapped ion with sensitivity to fluctuations at the sub-Hz level in a spectral range from quasi-dc up to 50 kHz.
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Affiliation(s)
- Alistair R Milne
- ARC Centre of Excellence for Engineered Quantum Systems, The University of Sydney, School of Physics, New South Wales 2006, Australia
| | - Cornelius Hempel
- ARC Centre of Excellence for Engineered Quantum Systems, The University of Sydney, School of Physics, New South Wales 2006, Australia
| | - Li Li
- Q-CTRL Pty Ltd, Sydney, New South Wales 2006, Australia
| | - Claire L Edmunds
- ARC Centre of Excellence for Engineered Quantum Systems, The University of Sydney, School of Physics, New South Wales 2006, Australia
| | | | - Harrison Ball
- Q-CTRL Pty Ltd, Sydney, New South Wales 2006, Australia
| | | | - Michael J Biercuk
- ARC Centre of Excellence for Engineered Quantum Systems, The University of Sydney, School of Physics, New South Wales 2006, Australia
- Q-CTRL Pty Ltd, Sydney, New South Wales 2006, Australia
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21
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Blümel R, Grzesiak N, Nguyen NH, Green AM, Li M, Maksymov A, Linke NM, Nam Y. Efficient Stabilized Two-Qubit Gates on a Trapped-Ion Quantum Computer. PHYSICAL REVIEW LETTERS 2021; 126:220503. [PMID: 34152167 DOI: 10.1103/physrevlett.126.220503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 05/04/2021] [Indexed: 06/13/2023]
Abstract
In order to scale up quantum processors and achieve a quantum advantage, it is crucial to economize on the power requirement of two-qubit gates, make them robust to drift in experimental parameters, and shorten the gate times. Applicable to all quantum computer architectures whose two-qubit gates rely on phase-space closure, we present here a new gate-optimizing principle according to which negligible amounts of gate fidelity are traded for substantial savings in power, which, in turn, can be traded for substantial increases in gate speed and/or qubit connectivity. As a concrete example, we illustrate the method by constructing optimal pulses for entangling gates on a pair of ions within a trapped-ion chain, one of the leading quantum computing architectures. Our method is direct, noniterative, and linear, and, in some parameter regimes, constructs gate-steering pulses requiring up to an order of magnitude less power than the standard method. Additionally, our method provides increased robustness to mode drift. We verify the new trade-off principle experimentally on our trapped-ion quantum computer.
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Affiliation(s)
- Reinhold Blümel
- Wesleyan University, Middletown, Connecticut 06459, USA
- IonQ, College Park, Maryland 20740, USA
| | | | - Nhung H Nguyen
- Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA
| | - Alaina M Green
- Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA
| | - Ming Li
- IonQ, College Park, Maryland 20740, USA
| | | | - Norbert M Linke
- Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA
| | - Yunseong Nam
- IonQ, College Park, Maryland 20740, USA
- Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA
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22
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Yun M, Guo FQ, Li M, Yan LL, Feng M, Li YX, Su SL. Distributed geometric quantum computation based on the optimized-control-technique in a cavity-atom system via exchanging virtual photons. OPTICS EXPRESS 2021; 29:8737-8750. [PMID: 33820315 DOI: 10.1364/oe.418626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 02/25/2021] [Indexed: 06/12/2023]
Abstract
We propose a scheme for quantum geometric computation on a fiber-cavity-fiber system, in which two atoms are located in two single-mode cavities, respectively, connected with each other by optical fiber. This scheme not only has the feature of virtual excitation of photons in the cavity quantum electrodynamics (CQED) that can reduce the effect of decay effectively but also has the advantage of geometric phase to withstand noises due to its built-in noise-resilience feature and robust merit. Specifically, our proposal combined with optimized-control-technology (OCT) can reduce gate operation error by adjusting the time-dependent amplitude and phase of the resonant field which further enhances the robustness of the quantum operation. The robustness against decoherence is demonstrated numerically and the scheme may be applied in the remote quantum information processing tasks and quantum computation.
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23
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Ren Z, Li W, Smerzi A, Gessner M. Metrological Detection of Multipartite Entanglement from Young Diagrams. PHYSICAL REVIEW LETTERS 2021; 126:080502. [PMID: 33709723 DOI: 10.1103/physrevlett.126.080502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 01/13/2021] [Indexed: 06/12/2023]
Abstract
We characterize metrologically useful multipartite entanglement by representing partitions with Young diagrams. We derive entanglement witnesses that are sensitive to the shape of Young diagrams and show that Dyson's rank acts as a resource for quantum metrology. Common quantifiers, such as the entanglement depth and k-separability are contained in this approach as the diagram's width and height. Our methods are experimentally accessible in a wide range of atomic systems, as we illustrate by analyzing published data on the quantum Fisher information and spin-squeezing coefficients.
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Affiliation(s)
- Zhihong Ren
- Institute of Theoretical Physics and Department of Physics, State Key Laboratory of Quantum Optics and Quantum Optics Devices, Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 Rue Lhomond, 75005 Paris, France
| | - Weidong Li
- Institute of Theoretical Physics and Department of Physics, State Key Laboratory of Quantum Optics and Quantum Optics Devices, Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
| | - Augusto Smerzi
- Institute of Theoretical Physics and Department of Physics, State Key Laboratory of Quantum Optics and Quantum Optics Devices, Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
- QSTAR, INO-CNR, and LENS, Largo Enrico Fermi 2, 50125 Firenze, Italy
| | - Manuel Gessner
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 Rue Lhomond, 75005 Paris, France
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24
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Abstract
Practical and useful quantum information processing requires substantial improvements with respect to current systems, both in the error rates of basic operations and in scale. The fundamental qualities of individual trapped-ion1 qubits are promising for long-term systems2, but the optics involved in their precise control are a barrier to scaling3. Planar-fabricated optics integrated within ion-trap devices can make such systems simultaneously more robust and parallelizable, as suggested by previous work with single ions4. Here we use scalable optics co-fabricated with a surface-electrode ion trap to achieve high-fidelity multi-ion quantum logic gates, which are often the limiting elements in building up the precise, large-scale entanglement that is essential to quantum computation. Light is efficiently delivered to a trap chip in a cryogenic environment via direct fibre coupling on multiple channels, eliminating the need for beam alignment into vacuum systems and cryostats and lending robustness to vibrations and beam-pointing drifts. This allows us to perform ground-state laser cooling of ion motion and to implement gates generating two-ion entangled states with fidelities greater than 99.3(2) per cent. This work demonstrates hardware that reduces noise and drifts in sensitive quantum logic, and simultaneously offers a route to practical parallelization for high-fidelity quantum processors5. Similar devices may also find applications in atom- and ion-based quantum sensing and timekeeping6.
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25
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Wang Y, Ding Y, Wang J, Chen X. Digital Quantum Simulation of Nonadiabatic Geometric Gates via Shortcuts to Adiabaticity. ENTROPY (BASEL, SWITZERLAND) 2020; 22:E1175. [PMID: 33286943 PMCID: PMC7597346 DOI: 10.3390/e22101175] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 10/15/2020] [Accepted: 10/16/2020] [Indexed: 11/28/2022]
Abstract
Geometric phases are used to construct quantum gates since it naturally resists local noises, acting as the modularized units of geometric quantum computing. Meanwhile, fast nonadiabatic geometric gates are required for reducing the information loss induced by decoherence. Here, we propose a digital simulation of nonadiabatic geometric quantum gates in terms of shortcuts to adiabaticity (STA). More specifically, we combine the invariant-based inverse engineering with optimal control theory for designing the fast and robust Abelian geometric gates against systematic error, in the context of two-level qubit systems. We exemplify X and T gates, in which the fidelities and robustness are evaluated by simulations in ideal quantum circuits. Our results can also be extended to constructing two-qubit gates, for example, a controlled-PHASE gate, which shares the equivalent effective Hamiltonian with rotation around the Z-axis of a single qubit. These STA-inspired nonadiabatic geometric gates can realize quantum error correction physically, leading to fault-tolerant quantum computing in the Noisy Intermediate-Scale Quantum (NISQ) era.
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Affiliation(s)
- Yapeng Wang
- International Center of Quantum Artificial Intelligence for Science and Technology (QuArtist) and Department of Physics, Shanghai University, Shanghai 200444, China; (Y.W.); (J.W.)
| | - Yongcheng Ding
- International Center of Quantum Artificial Intelligence for Science and Technology (QuArtist) and Department of Physics, Shanghai University, Shanghai 200444, China; (Y.W.); (J.W.)
- Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, 48080 Bilbao, Spain
| | - Jianan Wang
- International Center of Quantum Artificial Intelligence for Science and Technology (QuArtist) and Department of Physics, Shanghai University, Shanghai 200444, China; (Y.W.); (J.W.)
| | - Xi Chen
- International Center of Quantum Artificial Intelligence for Science and Technology (QuArtist) and Department of Physics, Shanghai University, Shanghai 200444, China; (Y.W.); (J.W.)
- Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, 48080 Bilbao, Spain
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26
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Wang Y, Crain S, Fang C, Zhang B, Huang S, Liang Q, Leung PH, Brown KR, Kim J. High-Fidelity Two-Qubit Gates Using a Microelectromechanical-System-Based Beam Steering System for Individual Qubit Addressing. PHYSICAL REVIEW LETTERS 2020; 125:150505. [PMID: 33095613 DOI: 10.1103/physrevlett.125.150505] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 07/17/2020] [Indexed: 06/11/2023]
Abstract
In a large scale trapped atomic ion quantum computer, high-fidelity two-qubit gates need to be extended over all qubits with individual control. We realize and characterize high-fidelity two-qubit gates in a system with up to four ions using radial modes. The ions are individually addressed by two tightly focused beams steered using microelectromechanical system mirrors. We deduce a gate fidelity of 99.49(7)% in a two-ion chain and 99.30(6)% in a four-ion chain by applying a sequence of up to 21 two-qubit gates and measuring the final state fidelity. We characterize the residual errors and discuss methods to further improve the gate fidelity towards values that are compatible with fault-tolerant quantum computation.
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Affiliation(s)
- Ye Wang
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Stephen Crain
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Chao Fang
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Bichen Zhang
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Shilin Huang
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Qiyao Liang
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
| | - Pak Hong Leung
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
| | - Kenneth R Brown
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
| | - Jungsang Kim
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
- IonQ, Inc., College Park, Maryland 20740, USA
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27
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Hughes AC, Schäfer VM, Thirumalai K, Nadlinger DP, Woodrow SR, Lucas DM, Ballance CJ. Benchmarking a High-Fidelity Mixed-Species Entangling Gate. PHYSICAL REVIEW LETTERS 2020; 125:080504. [PMID: 32909787 DOI: 10.1103/physrevlett.125.080504] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 07/08/2020] [Indexed: 06/11/2023]
Abstract
We implement a two-qubit logic gate between a ^{43}Ca^{+} hyperfine qubit and a ^{88}Sr^{+} Zeeman qubit. For this pair of ion species, the S-P optical transitions are close enough that a single laser of wavelength 402 nm can be used to drive the gate but sufficiently well separated to give good spectral isolation and low photon scattering errors. We characterize the gate by full randomized benchmarking, gate set tomography, and Bell state analysis. The latter method gives a fidelity of 99.8(1)%, comparable to that of the best same-species gates and consistent with known sources of error.
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Affiliation(s)
- A C Hughes
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - V M Schäfer
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - K Thirumalai
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - D P Nadlinger
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - S R Woodrow
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - D M Lucas
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - C J Ballance
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
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28
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Yanagimoto R, Onodera T, Ng E, Wright LG, McMahon PL, Mabuchi H. Engineering a Kerr-Based Deterministic Cubic Phase Gate via Gaussian Operations. PHYSICAL REVIEW LETTERS 2020; 124:240503. [PMID: 32639814 DOI: 10.1103/physrevlett.124.240503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 05/26/2020] [Indexed: 06/11/2023]
Abstract
We propose a deterministic, measurement-free implementation of a cubic phase gate for continuous-variable quantum information processing. In our scheme, the applications of displacement and squeezing operations allow us to engineer the effective evolution of the quantum state propagating through an optical Kerr nonlinearity. Under appropriate conditions, we show that the input state evolves according to a cubic phase Hamiltonian, and we find that the cubic phase gate error decreases inverse quartically with the amount of quadrature squeezing, even in the presence of linear loss. We also show how our scheme can be adapted to deterministically generate a nonclassical approximate cubic phase state with high fidelity using a ratio of native nonlinearity to linear loss of only 10^{-4}, indicating that our approach may be experimentally viable in the near term even on all-optical platforms, e.g., using quantum solitons in pulsed nonlinear nanophotonics.
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Affiliation(s)
- Ryotatsu Yanagimoto
- E. L. Ginzton Laboratory, Stanford University, Stanford, California 94305, USA
| | - Tatsuhiro Onodera
- E. L. Ginzton Laboratory, Stanford University, Stanford, California 94305, USA
- NTT Physics and Informatics Laboratories, NTT Research, Inc., 1950 University Ave. East Palo Alto, California 94303, USA
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - Edwin Ng
- E. L. Ginzton Laboratory, Stanford University, Stanford, California 94305, USA
| | - Logan G Wright
- E. L. Ginzton Laboratory, Stanford University, Stanford, California 94305, USA
- NTT Physics and Informatics Laboratories, NTT Research, Inc., 1950 University Ave. East Palo Alto, California 94303, USA
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - Peter L McMahon
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - Hideo Mabuchi
- E. L. Ginzton Laboratory, Stanford University, Stanford, California 94305, USA
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29
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Zhang Q, Hao H, Ren J, Zhang F, Gong Q, Gu Y. A quantum phase gate capable of effectively collecting photons based on a gap plasmon structure. NANOSCALE 2020; 12:10082-10089. [PMID: 32347868 DOI: 10.1039/d0nr00496k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The realization of a quantum phase gate in micro-nano structures is beneficial to the miniaturization and integration of on-chip quantum circuits. Surface plasmons are well known for ultra-small mode volumes, which can further reduce the size of quantum devices. However, high fidelity quantum phase gates using surface plasmon nanocavities in a strong coupling regime have not been proposed yet. Here, based on a metallic nanocone-nanowire structure, we theoretically demonstrate a quantum phase gate, simultaneously achieving an arbitrary phase shift and effective photon collection at the nanoscale. The gate can reach 88.8% fidelity due to combining the enhanced coupling coefficient achievable by gap plasmons with low cavity loss resulting from gain medium. Meanwhile, emitted photons can be guided via the nanowire with collection efficiency over 30%. The system may act as universal quantum nodes that can process and store quantum information. It also holds promise for the physical implementation of on-chip multifunctional quantum gates and novel quantum circuits.
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Affiliation(s)
- Qi Zhang
- State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing 100871, China.
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30
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A Quantum Heat Exchanger for Nanotechnology. ENTROPY 2020; 22:e22040379. [PMID: 33286156 PMCID: PMC7516853 DOI: 10.3390/e22040379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 03/17/2020] [Accepted: 03/21/2020] [Indexed: 11/17/2022]
Abstract
In this paper, we design a quantum heat exchanger which converts heat into light on relatively short quantum optical time scales. Our scheme takes advantage of heat transfer as well as collective cavity-mediated laser cooling of an atomic gas inside a cavitating bubble. Laser cooling routinely transfers individually trapped ions to nano-Kelvin temperatures for applications in quantum technology. The quantum heat exchanger which we propose here might be able to provide cooling rates of the order of Kelvin temperatures per millisecond and is expected to find applications in micro- and nanotechnology.
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31
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Latmiral L, Armata F. Berry-Hannay relation in nonlinear optomechanics. Sci Rep 2020; 10:2264. [PMID: 32042012 PMCID: PMC7010711 DOI: 10.1038/s41598-020-59081-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 01/22/2020] [Indexed: 12/03/2022] Open
Abstract
We address the quantum-classical comparison of phase measurements in optomechanics in the general framework of Berry phases for composite systems. While the relation between Berry phase and Hannay angle has been proven for a large set of quadratic Hamiltonians, such correspondence has not been shown so far in the case of non-linear interactions (e.g. when three or more operators are involved). Remarkably, considering the full optomechanical interaction we recover the aforementioned mathematical relation with the Hannay angle obtained from classical equations of motion. Our results link at a fundamental level previous proposals to measure decoherence, such as the one expressed by Marshall et al., with the no-go theorem shown by Armata et al., which provides boundaries to understand the quantum-to-classical transition in optomechanics.
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Affiliation(s)
- Ludovico Latmiral
- QOLS, Blackett Laboratory, Imperial College London, London, SW7 2AZ, United Kingdom.
| | - Federico Armata
- QOLS, Blackett Laboratory, Imperial College London, London, SW7 2AZ, United Kingdom.
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32
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Qi WR, Liu R, Kong LJ, Wang ZX, Huang SY, Tu C, Li Y, Wang HT. Pancharatnam-Berry geometric phase memory based on spontaneous parametric down-conversion. OPTICS LETTERS 2020; 45:682-685. [PMID: 32004284 DOI: 10.1364/ol.384363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 12/27/2019] [Indexed: 06/10/2023]
Abstract
Phase memory is an effect in which the interaction between a coherent pump beam and a nonlinear crystal generates photon pairs via the spontaneous parametric down-conversion process, then the down-converted photons (signal and idler) can carry the phase information of the pump beam. There has been much research on the memory of the dynamic phase so far; however, there is no report on the memory of non-dynamic phase, to the best of our knowledge. Here we acquire a Pancharatnam-Berry (PB) geometric phase in a physical system when light travels along a trajectory in polarization-state space. Induced coherence occurs in a cascaded scheme composed of two nonlinear crystals, when the idler photons in both crystals are aligned to be indistinguishable. A NOON ($N\; = \;{2}$N=2) state is established when blocking the two idler photons. We explore the PB geometric phase memory of the NOON state and induced coherence. We find that the first-order interference of the two-photon state or signal photons can be controlled by introducing the PB geometric phase to the pump light. This may facilitate precise control of the phase of the down-converted photons.
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33
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Kienzler D, Wan Y, Erickson SD, Wu JJ, Wilson AC, Wineland DJ, Leibfried D. Quantum Logic Spectroscopy with Ions in Thermal Motion. PHYSICAL REVIEW. X 2020; 10:10.1103/PhysRevX.10.021012. [PMID: 34136310 PMCID: PMC8204399 DOI: 10.1103/physrevx.10.021012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
A mixed-species geometric phase gate has been proposed for implementing quantum logic spectroscopy on trapped ions, which combines probe and information transfer from the spectroscopy to the logic ion in a single pulse. We experimentally realize this method, show how it can be applied as a technique for identifying transitions in currently intractable atoms or molecules, demonstrate its reduced temperature sensitivity, and observe quantum-enhanced frequency sensitivity when it is applied to multi-ion chains. Potential applications include improved readout of trapped-ion clocks and simplified error syndrome measurements for quantum error correction.
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Affiliation(s)
- D. Kienzler
- National Institute of Standards and Technology, Time and Frequency Division 688, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80305, USA
| | - Y. Wan
- National Institute of Standards and Technology, Time and Frequency Division 688, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80305, USA
| | - S. D. Erickson
- National Institute of Standards and Technology, Time and Frequency Division 688, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80305, USA
| | - J. J. Wu
- National Institute of Standards and Technology, Time and Frequency Division 688, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80305, USA
| | - A. C. Wilson
- National Institute of Standards and Technology, Time and Frequency Division 688, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80305, USA
| | - D. J. Wineland
- National Institute of Standards and Technology, Time and Frequency Division 688, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80305, USA
- Department of Physics, University of Oregon, Eugene, Oregon 97403, USA
| | - D. Leibfried
- National Institute of Standards and Technology, Time and Frequency Division 688, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80305, USA
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34
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Cui JM, Ai MZ, He R, Qian ZH, Qin XK, Huang YF, Zhou ZW, Li CF, Tu T, Guo GC. Experimental demonstration of suppressing residual geometric dephasing. Sci Bull (Beijing) 2019; 64:1757-1763. [PMID: 36659534 DOI: 10.1016/j.scib.2019.09.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 08/01/2019] [Accepted: 08/23/2019] [Indexed: 01/21/2023]
Abstract
The geometric phase is regarded as a promising strategy in fault tolerance quantum information processing (QIP) domain due to its phase only depending on the geometry of the path executed. However, decoherence caused by environmental noise will destroy the geometric phase. Traditional dynamic decoupling sequences can eliminate dynamic dephasing but can not reduce residual geometric dephasing, which is still vital for high-precision quantum manipulation. In this work, we experimentally demonstrate effective suppression of residual geometric dephasing with modified dynamic decoupling schemes, using a single trapped 171Yb+ ion. The experimental results show that the modified schemes can reduce dephasing rate up to more than one order of magnitude compared with traditional dynamic decoupling schemes, where residual geometric dephasing dominates. Besides, we also investigate the impact of intensity and correlation time of the low-frequency noise on coherence of the quantum system. And we confirm these methods can be used in many cases.
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Affiliation(s)
- Jin-Ming Cui
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China; CAS Center For Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Ming-Zhong Ai
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China; CAS Center For Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Ran He
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China; CAS Center For Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Zhong-Hua Qian
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China; CAS Center For Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Xiao-Ke Qin
- Luoyang Institute of Electro-Optical Equipment, AVIC, Luoyang 471000, China
| | - Yun-Feng Huang
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China; CAS Center For Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China.
| | - Zheng-Wei Zhou
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China; CAS Center For Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China.
| | - Chuan-Feng Li
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China; CAS Center For Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China.
| | - Tao Tu
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China; CAS Center For Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Guang-Can Guo
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China; CAS Center For Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
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35
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H M B, Boguslawski M, Barrios M, Xin L, Chapman MS. Exploring Non-Abelian Geometric Phases in Spin-1 Ultracold Atoms. PHYSICAL REVIEW LETTERS 2019; 123:173202. [PMID: 31702240 DOI: 10.1103/physrevlett.123.173202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Indexed: 06/10/2023]
Abstract
The spin vector of a spin-1 system, unlike that of a spin-1/2 system, can lie anywhere on or inside the Bloch sphere representing the phase space. As a consequence, the geometrical and topological properties of the spin-1 phase space of quantum states are richer and require a generalization of Berry's phase. For special trajectories passing through the center of the Bloch sphere (singular loops), the geometric phase has a non-Abelian nature. Here, we experimentally explore this geometric phase for singular loops in a spin-1 quantum system using ultracold ^{87}Rb atoms confined in an optical trap using microwave and rf control fields.
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Affiliation(s)
- Bharath H M
- School of Physics, Georgia Institute of Technology, 837 State Street NW, Atlanta, Georgia 30332, USA
- Fakultät für Physik, Ludwig-Maximilians-Univesität München, 4 Schellingstraße, 80799 München, Germany
- Max-Planck-Institut für Quantenoptik, 85748 Garching, Germany
| | - Matthew Boguslawski
- School of Physics, Georgia Institute of Technology, 837 State Street NW, Atlanta, Georgia 30332, USA
| | - Maryrose Barrios
- School of Physics, Georgia Institute of Technology, 837 State Street NW, Atlanta, Georgia 30332, USA
| | - Lin Xin
- School of Physics, Georgia Institute of Technology, 837 State Street NW, Atlanta, Georgia 30332, USA
| | - Michael S Chapman
- School of Physics, Georgia Institute of Technology, 837 State Street NW, Atlanta, Georgia 30332, USA
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36
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Liang YC, Yeh YH, Mendonça PEMF, Teh RY, Reid MD, Drummond PD. Quantum fidelity measures for mixed states. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2019; 82:076001. [PMID: 31022705 DOI: 10.1088/1361-6633/ab1ca4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Applications of quantum technology often require fidelities to quantify performance. These provide a fundamental yardstick for the comparison of two quantum states. While this is straightforward in the case of pure states, it is much more subtle for the more general case of mixed quantum states often found in practice. A large number of different proposals exist. In this review, we summarize the required properties of a quantum fidelity measure, and compare them, to determine which properties each of the different measures has. We show that there are large classes of measures that satisfy all the required properties of a fidelity measure, just as there are many norms of Hilbert space operators, and many measures of entropy. We compare these fidelities, with detailed proofs of their properties. We also summarize briefly the applications of these measures in teleportation, quantum memories and quantum computers, quantum communications, and quantum phase-space simulations.
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Affiliation(s)
- Yeong-Cherng Liang
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan. Center for Quantum Frontiers of Research & Technology (QFort), National Cheng Kung University, Tainan 701, Taiwan
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37
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Simeonov LS, Vitanov NV, Ivanov PA. Compensation of the trap-induced quadrupole interaction in trapped Rydberg ions. Sci Rep 2019; 9:7340. [PMID: 31089243 PMCID: PMC6517410 DOI: 10.1038/s41598-019-43865-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 04/27/2019] [Indexed: 11/09/2022] Open
Abstract
The quadrupole interaction between the Rydberg electronic states of a Rydberg ion and the radio frequency electric field of the ion trap is analyzed. Such a coupling is negligible for the lowest energy levels of a trapped ion but it is important for a trapped Rydberg ion due to its large electric quadrupole moment. This coupling cannot be neglected by the standard rotating-wave approximation because it is comparable to the frequency of the trapping electric field. We investigate the effect of the quadrupole coupling by performing a suitable effective representation of the Hamiltonian. For a single ion we show that in this effective picture the quadrupole interaction is replaced by rescaled laser intensities and additional Stark shifts of the Rydberg levels. Hence this detrimental quadrupole coupling can be efficiently compensated by an appropriate increase of the Rabi frequencies. Moreover, we consider the strong dipole-dipole interaction between a pair of Rydberg ions in the presence of the quadrupole coupling. In the effective representation we observe reducing of the dipole-dipole coupling as well as additional spin-spin interaction.
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Affiliation(s)
- Lachezar S Simeonov
- Department of Physics, St. Kliment Ohridski University of Sofia, 5 James Bourchier blvd, 1164, Sofia, Bulgaria
| | - Nikolay V Vitanov
- Department of Physics, St. Kliment Ohridski University of Sofia, 5 James Bourchier blvd, 1164, Sofia, Bulgaria
| | - Peter A Ivanov
- Department of Physics, St. Kliment Ohridski University of Sofia, 5 James Bourchier blvd, 1164, Sofia, Bulgaria.
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38
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Li J, Wang G, Xiao R, Sun C, Wu C, Xue K. Multi-qubit Quantum Rabi Model and Multi-partite Entangled States in a Circuit QED System. Sci Rep 2019; 9:1380. [PMID: 30718592 PMCID: PMC6362268 DOI: 10.1038/s41598-018-35751-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 11/10/2018] [Indexed: 11/24/2022] Open
Abstract
Multi-qubit quantum Rabi model, which is a fundamental model describing light-matter interaction, plays an important role in various physical systems. In this paper, we propose a theoretical method to simulate multi-qubit quantum Rabi model in a circuit quantum electrodynamics system. By means of external transversal and longitudinal driving fields, an effective Hamiltonian describing the multi-qubit quantum Rabi model is derived. The effective frequency of the resonator and the effective splitting of the qubits depend on the external driving fields. By adjusting the frequencies and the amplitudes of the driving fields, the stronger coupling regimes could be reached. The numerical simulation shows that our proposal works well in a wide range of parameter space. Moreover, our scheme can be utilized to generate two-qubit gate, Schrödinger states, and multi-qubit GHZ states. The maximum displacement of the Schrödinger cat states can be enhanced by increasing the number of the qubits and the relative coupling strength. It should be mention that we can obtain high fidelity Schrödinger cat states and multi-qubit GHZ states even the system suffering dissipation. The presented proposal may open a way to study the stronger coupling regimes whose coupling strength is far away from ultrastrong coupling regimes.
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Affiliation(s)
- Jialun Li
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun, 130024, China
| | - Gangcheng Wang
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun, 130024, China.
| | - Ruoqi Xiao
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun, 130024, China
| | - Chunfang Sun
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun, 130024, China.
| | - Chunfeng Wu
- Science and Mathematics, and Pillar of Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Road, Singapore, 487372, Singapore
| | - Kang Xue
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun, 130024, China.
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39
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Ge W, Sawyer BC, Britton JW, Jacobs K, Bollinger JJ, Foss-Feig M. Trapped Ion Quantum Information Processing with Squeezed Phonons. PHYSICAL REVIEW LETTERS 2019; 122:030501. [PMID: 30735427 DOI: 10.1103/physrevlett.122.030501] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Indexed: 06/09/2023]
Abstract
Trapped ions offer a pristine platform for quantum computation and simulation, but improving their coherence remains a crucial challenge. Here, we propose and analyze a new strategy to enhance the coherent interactions in trapped ion systems via parametric amplification of the ions' motion-by squeezing the collective motional modes (phonons), the spin-spin interactions they mediate can be significantly enhanced. We illustrate the power of this approach by showing how it can enhance collective spin states useful for quantum metrology, and how it can improve the speed and fidelity of two-qubit gates in multi-ion systems, important ingredients for scalable trapped ion quantum computation. Our results are also directly relevant to numerous other physical platforms in which spin interactions are mediated by bosons.
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Affiliation(s)
- Wenchao Ge
- United States Army Research Laboratory, Adelphi, Maryland 20783, USA
- The Institute for Research in Electronics and Applied Physics (IREAP), College Park, Maryland 20740, USA
| | - Brian C Sawyer
- Georgia Tech Research Institute, Atlanta, Georgia 30332, USA
| | - Joseph W Britton
- United States Army Research Laboratory, Adelphi, Maryland 20783, USA
| | - Kurt Jacobs
- United States Army Research Laboratory, Adelphi, Maryland 20783, USA
- Department of Physics, University of Massachusetts at Boston, Boston, Massachusetts 02125, USA
- Hearne Institute for Theoretical Physics, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - John J Bollinger
- National Institute of Standards and Technology, Boulder, Colorado 80305, USA
| | - Michael Foss-Feig
- United States Army Research Laboratory, Adelphi, Maryland 20783, USA
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
- Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, Maryland 20742, USA
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40
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Di Stefano O, Settineri A, Macrì V, Ridolfo A, Stassi R, Kockum AF, Savasta S, Nori F. Interaction of Mechanical Oscillators Mediated by the Exchange of Virtual Photon Pairs. PHYSICAL REVIEW LETTERS 2019; 122:030402. [PMID: 30735421 DOI: 10.1103/physrevlett.122.030402] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Indexed: 06/09/2023]
Abstract
Two close parallel mirrors attract due to a small force (Casimir effect) originating from the quantum vacuum fluctuations of the electromagnetic field. These vacuum fluctuations can also induce motional forces exerted upon one mirror when the other one moves. Here, we consider an optomechanical system consisting of two vibrating mirrors constituting an optical resonator. We find that motional forces can determine noticeable coupling rates between the two spatially separated vibrating mirrors. We show that, by tuning the two mechanical oscillators into resonance, energy is exchanged between them at the quantum level. This coherent motional coupling is enabled by the exchange of virtual photon pairs, originating from the dynamical Casimir effect. The process proposed here shows that the electromagnetic quantum vacuum is able to transfer mechanical energy somewhat like an ordinary fluid. We show that this system can also operate as a mechanical parametric down-converter even at very weak excitations. These results demonstrate that vacuum-induced motional forces open up new possibilities for the development of optomechanical quantum technologies.
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Affiliation(s)
- Omar Di Stefano
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
| | - Alessio Settineri
- Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, Università di Messina, I-98166 Messina, Italy
| | - Vincenzo Macrì
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
| | - Alessandro Ridolfo
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
- Dipartimento di Fisica e Astronomia, Universitá di Catania, I-95123 Catania, Italy
| | - Roberto Stassi
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
| | - Anton Frisk Kockum
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
- Wallenberg Centre for Quantum Technology, Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Salvatore Savasta
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
- Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, Università di Messina, I-98166 Messina, Italy
| | - Franco Nori
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
- Physics Department, The University of Michigan, Ann Arbor, Michigan 48109-1040, USA
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41
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Huang YY, Wu YK, Wang F, Hou PY, Wang WB, Zhang WG, Lian WQ, Liu YQ, Wang HY, Zhang HY, He L, Chang XY, Xu Y, Duan LM. Experimental Realization of Robust Geometric Quantum Gates with Solid-State Spins. PHYSICAL REVIEW LETTERS 2019; 122:010503. [PMID: 31012688 DOI: 10.1103/physrevlett.122.010503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Indexed: 06/09/2023]
Abstract
We experimentally realize a universal set of single-bit and two-bit geometric quantum gates by adiabatically controlling solid-state spins in a diamond defect. Compared with the nonadiabatic approach, the adiabatic scheme for geometric quantum computation offers a unique advantage of inherent robustness to parameter variations, which is explicitly demonstrated in our experiment by showing that the single-bit gates remain unchanged when the driving field amplitude varies by a factor of 2 or the detuning fluctuates in a range comparable to the inverse of the gate time. The reported adiabatic control technique and its convenient implementation offer a paradigm for achieving quantum computation through robust geometric quantum gates, which is important for quantum information systems with parameter-fluctuation noise such as those from the inhomogeneous coupling or the spectral diffusion.
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Affiliation(s)
- Y-Y Huang
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, People's Republic of China
| | - Y-K Wu
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - F Wang
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, People's Republic of China
| | - P-Y Hou
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, People's Republic of China
| | - W-B Wang
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, People's Republic of China
| | - W-G Zhang
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, People's Republic of China
| | - W-Q Lian
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, People's Republic of China
| | - Y-Q Liu
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, People's Republic of China
| | - H-Y Wang
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, People's Republic of China
| | - H-Y Zhang
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, People's Republic of China
| | - L He
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, People's Republic of China
| | - X-Y Chang
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, People's Republic of China
| | - Y Xu
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, People's Republic of China
| | - L-M Duan
- Center for Quantum Information, IIIS, Tsinghua University, Beijing 100084, People's Republic of China
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
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42
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Sutherland RT, Srinivas R, Burd SC, Leibfried D, Wilson AC, Wineland DJ, Allcock DTC, Slichter DH, Libby SB. Versatile laser-free trapped-ion entangling gates. NEW JOURNAL OF PHYSICS 2019; 21:10.1088/1367-2630/ab0be5. [PMID: 31555055 PMCID: PMC6759860 DOI: 10.1088/1367-2630/ab0be5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We present a general theory for laser-free entangling gates with trapped-ion hyperfine qubits, using either static or oscillating magnetic-field gradients combined with a pair of uniform microwave fields symmetrically detuned about the qubit frequency. By transforming into a 'bichromatic' interaction picture, we show that eitherσ ^ ϕ ⊗ σ ^ ϕ orσ ^ z ⊗ σ ^ z geometric phase gates can be performed. The gate basis is determined by selecting the microwave detuning. The driving parameters can be tuned to provide intrinsic dynamical decoupling from qubit frequency fluctuations. Theσ ^ z ⊗ σ ^ z gates can be implemented in a novel manner which eases experimental constraints. We present numerical simulations of gate fidelities assuming realistic parameters.
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Affiliation(s)
- R T Sutherland
- Physics Division, Physical and Life Sciences, Lawrence Livermore National Laboratory, Livermore, CA 94550, United States of America
| | - R Srinivas
- Time and Frequency Division, National Institute of Standards and Technology, Boulder, CO 80305, United States of America
- Department of Physics, University of Colorado, Boulder, CO 80309, United States of America
| | - S C Burd
- Time and Frequency Division, National Institute of Standards and Technology, Boulder, CO 80305, United States of America
- Department of Physics, University of Colorado, Boulder, CO 80309, United States of America
| | - D Leibfried
- Time and Frequency Division, National Institute of Standards and Technology, Boulder, CO 80305, United States of America
| | - A C Wilson
- Time and Frequency Division, National Institute of Standards and Technology, Boulder, CO 80305, United States of America
| | - D J Wineland
- Time and Frequency Division, National Institute of Standards and Technology, Boulder, CO 80305, United States of America
- Department of Physics, University of Colorado, Boulder, CO 80309, United States of America
- Department of Physics, University of Oregon, Eugene, OR 97403, United States of America
| | - D T C Allcock
- Time and Frequency Division, National Institute of Standards and Technology, Boulder, CO 80305, United States of America
- Department of Physics, University of Colorado, Boulder, CO 80309, United States of America
- Department of Physics, University of Oregon, Eugene, OR 97403, United States of America
| | - D H Slichter
- Time and Frequency Division, National Institute of Standards and Technology, Boulder, CO 80305, United States of America
| | - S B Libby
- Physics Division, Physical and Life Sciences, Lawrence Livermore National Laboratory, Livermore, CA 94550, United States of America
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43
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Shyshlov D, Babikov D. Computational study of cold ions trapped in a double-well potential. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1559956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
| | - Dmitri Babikov
- Chemistry Department, Marquette University, Milwaukee, USA
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44
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Abstract
A key challenge of magnetometry lies in the simultaneous optimization of magnetic field sensitivity and maximum field range. In interferometry-based magnetometry, a quantum two-level system acquires a dynamic phase in response to an applied magnetic field. However, due to the 2π periodicity of the phase, increasing the coherent interrogation time to improve sensitivity reduces field range. Here we introduce a route towards both large magnetic field range and high sensitivity via measurements of the geometric phase acquired by a quantum two-level system. We experimentally demonstrate geometric-phase magnetometry using the electronic spin associated with the nitrogen vacancy (NV) color center in diamond. Our approach enables unwrapping of the 2π phase ambiguity, enhancing field range by 400 times. We also find additional sensitivity improvement in the nonadiabatic regime, and study how geometric-phase decoherence depends on adiabaticity. Our results show that the geometric phase can be a versatile tool for quantum sensing applications. When performing interferometry-based magnetometry, there is generally a trade-off between sensitivity and range. Here, instead, the authors demonstrate a geometric-phase-based protocol which allows a 400-fold enhancement in static magnetic field range with a single NV-centre without reducing sensitivity.
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45
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Webb AE, Webster SC, Collingbourne S, Bretaud D, Lawrence AM, Weidt S, Mintert F, Hensinger WK. Resilient Entangling Gates for Trapped Ions. PHYSICAL REVIEW LETTERS 2018; 121:180501. [PMID: 30444422 DOI: 10.1103/physrevlett.121.180501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Indexed: 06/09/2023]
Abstract
Constructing a large-scale ion trap quantum processor will require entangling gate operations that are robust in the presence of noise and experimental imperfection. We experimentally demonstrate how a new type of Mølmer-Sørensen gate protects against infidelity caused by heating of the motional mode used during the gate. Furthermore, we show how the same technique simultaneously provides significant protection against slow fluctuations and mis-sets in the secular frequency. Since this parameter sensitivity is worsened in cases where the ions are not ground-state cooled, our method provides a path towards relaxing ion cooling requirements in practical realizations of quantum computing and simulation.
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Affiliation(s)
- A E Webb
- Department of Physics and Astronomy, University of Sussex, Brighton, BN1 9QH, United Kingdom
| | - S C Webster
- Department of Physics and Astronomy, University of Sussex, Brighton, BN1 9QH, United Kingdom
| | - S Collingbourne
- QOLS, Blackett Laboratory, Imperial College London, London, SW7 2BW, United Kingdom
| | - D Bretaud
- Department of Physics and Astronomy, University of Sussex, Brighton, BN1 9QH, United Kingdom
- QOLS, Blackett Laboratory, Imperial College London, London, SW7 2BW, United Kingdom
| | - A M Lawrence
- Department of Physics and Astronomy, University of Sussex, Brighton, BN1 9QH, United Kingdom
- QOLS, Blackett Laboratory, Imperial College London, London, SW7 2BW, United Kingdom
| | - S Weidt
- Department of Physics and Astronomy, University of Sussex, Brighton, BN1 9QH, United Kingdom
| | - F Mintert
- QOLS, Blackett Laboratory, Imperial College London, London, SW7 2BW, United Kingdom
| | - W K Hensinger
- Department of Physics and Astronomy, University of Sussex, Brighton, BN1 9QH, United Kingdom
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46
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Shapira Y, Shaniv R, Manovitz T, Akerman N, Ozeri R. Robust Entanglement Gates for Trapped-Ion Qubits. PHYSICAL REVIEW LETTERS 2018; 121:180502. [PMID: 30444416 DOI: 10.1103/physrevlett.121.180502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Indexed: 06/09/2023]
Abstract
High-fidelity two-qubit entangling gates play an important role in many quantum information processing tasks and are a necessary building block for constructing a universal quantum computer. Such high-fidelity gates have been demonstrated on trapped-ion qubits; however, control errors and noise in gate parameters may still lead to reduced fidelity. Here we propose and demonstrate a general family of two-qubit entangling gates which are robust to different sources of noise and control errors. These gates generalize the renowned Mølmer-Sørensen gate by using multitone drives. We experimentally implemented several of the proposed gates on ^{88}Sr^{+} ions trapped in a linear Paul trap and verified their resilience.
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Affiliation(s)
- Yotam Shapira
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Ravid Shaniv
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Tom Manovitz
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Nitzan Akerman
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Roee Ozeri
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
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47
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Nagata K, Kuramitani K, Sekiguchi Y, Kosaka H. Universal holonomic quantum gates over geometric spin qubits with polarised microwaves. Nat Commun 2018; 9:3227. [PMID: 30104616 PMCID: PMC6089953 DOI: 10.1038/s41467-018-05664-w] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 07/11/2018] [Indexed: 12/02/2022] Open
Abstract
A microwave shares a nonintuitive phase called the geometric phase with an interacting electron spin after an elastic scattering. The geometric phase, generally discarded as a global phase, allows universal holonomic gating of an ideal logical qubit, which we call a geometric spin qubit, defined in the degenerate subspace of the triplet spin qutrit. We here experimentally demonstrate nonadiabatic and non-abelian holonomic quantum gates over the geometric spin qubit on an electron or nitrogen nucleus. We manipulate purely the geometric phase with a polarised microwave in a nitrogen-vacancy centre in diamond under a zero-magnetic field at room temperature. We also demonstrate a two-qubit holonomic gate to show universality by manipulating the electron−nucleus entanglement. The universal holonomic gates enable fast and fault-tolerant manipulation for realising quantum repeaters interfacing between universal quantum computers and secure communication networks. Holonomic quantum gates represent a promising route to noise-tolerant quantum operations. Here, the authors use polarised microwaves to implement nonadiabatic holonomic quantum gates at room temperature and zero magnetic field on NV centers, both on single-qubit and between electron and nuclear spins.
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Affiliation(s)
- Kodai Nagata
- Yokohama National University, 79-5 Tokiwadai, Hodogaya, Yokohama, 240-8501, Japan
| | - Kouyou Kuramitani
- Yokohama National University, 79-5 Tokiwadai, Hodogaya, Yokohama, 240-8501, Japan
| | - Yuhei Sekiguchi
- Yokohama National University, 79-5 Tokiwadai, Hodogaya, Yokohama, 240-8501, Japan
| | - Hideo Kosaka
- Yokohama National University, 79-5 Tokiwadai, Hodogaya, Yokohama, 240-8501, Japan.
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48
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Bleu O, Malpuech G, Gao Y, Solnyshkov DD. Effective Theory of Nonadiabatic Quantum Evolution Based on the Quantum Geometric Tensor. PHYSICAL REVIEW LETTERS 2018; 121:020401. [PMID: 30085704 DOI: 10.1103/physrevlett.121.020401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Indexed: 06/08/2023]
Abstract
We study the role of the quantum geometric tensor (QGT) in the evolution of two-band quantum systems. We show that all its components play an important role on the extra phase acquired by a spinor and on the trajectory of an accelerated wave packet in any realistic finite-duration experiment. While the adiabatic phase is determined by the Berry curvature (the imaginary part of the tensor), the nonadiabaticity is determined by the quantum metric (the real part of the tensor). We derive, for geodesic trajectories (corresponding to acceleration from zero initial velocity), the semiclassical equations of motion with nonadiabatic corrections. The particular case of a planar microcavity in the strong coupling regime allows us to extract the QGT components by direct light polarization measurements and to check their effects on the quantum evolution.
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Affiliation(s)
- O Bleu
- Institut Pascal, PHOTON-N2, University Clermont Auvergne, CNRS, 4 avenue Blaise Pascal, 63178 Aubière Cedex, France
| | - G Malpuech
- Institut Pascal, PHOTON-N2, University Clermont Auvergne, CNRS, 4 avenue Blaise Pascal, 63178 Aubière Cedex, France
| | - Y Gao
- Department of Physics, Carnegie-Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - D D Solnyshkov
- Institut Pascal, PHOTON-N2, University Clermont Auvergne, CNRS, 4 avenue Blaise Pascal, 63178 Aubière Cedex, France
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49
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Shaniv R, Manovitz T, Shapira Y, Akerman N, Ozeri R. Toward Heisenberg-Limited Rabi Spectroscopy. PHYSICAL REVIEW LETTERS 2018; 120:243603. [PMID: 29957010 DOI: 10.1103/physrevlett.120.243603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 12/25/2017] [Indexed: 06/08/2023]
Abstract
The use of entangled states was shown to improve the fundamental limits of spectroscopy to beyond the standard-quantum limit. Here, rather than probing the free evolution of the phase of an entangled state with respect to a local oscillator, we probe the evolution of an initially separable two-atom register under an Ising spin Hamiltonian with a transverse field. The resulting correlated spin-rotation spectrum is twice as narrow as that of an uncorrelated rotation. We implement this ideally Heisenberg-limited Rabi spectroscopy scheme on the optical-clock electric-quadrupole transition of ^{88}Sr^{+} using a two-ion crystal. We further show that depending on the initial state, correlated rotation can occur in two orthogonal subspaces of the full Hilbert space, yielding entanglement-enhanced spectroscopy of either the average transition frequency of the two ions or their difference from the mean frequency. The use of correlated spin rotations can potentially lead to new paths for clock stability improvement.
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Affiliation(s)
- Ravid Shaniv
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Tom Manovitz
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Yotam Shapira
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Nitzan Akerman
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Roee Ozeri
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
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50
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Ratcliffe AK, Taylor RL, Hope JJ, Carvalho ARR. Scaling Trapped Ion Quantum Computers Using Fast Gates and Microtraps. PHYSICAL REVIEW LETTERS 2018; 120:220501. [PMID: 29906140 DOI: 10.1103/physrevlett.120.220501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Indexed: 06/08/2023]
Abstract
Most attempts to produce a scalable quantum information processing platform based on ion traps have focused on the shuttling of ions in segmented traps. We show that an architecture based on an array of microtraps with fast gates will outperform architectures based on ion shuttling. This system requires higher power lasers but does not require the manipulation of potentials or shuttling of ions. This improves optical access, reduces the complexity of the trap, and reduces the number of conductive surfaces close to the ions. The use of fast gates also removes limitations on the gate time. Error rates of 10^{-5} are shown to be possible with 250 mW laser power and a trap separation of 100 μm. The performance of the gates is shown to be robust to the limitations in the laser repetition rate and the presence of many ions in the trap array.
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Affiliation(s)
- Alexander K Ratcliffe
- Department of Quantum Science, RSPE, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Richard L Taylor
- Department of Quantum Science, RSPE, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Joseph J Hope
- Department of Quantum Science, RSPE, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - André R R Carvalho
- Centre for Quantum Dynamics, Griffith University, Gold Coast, Queensland 4222, Australia
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