1
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Lee W, Chung D, Kang J, Jeon H, Jung C, Cho DID, Kim T. Micromotion compensation of trapped ions by qubit transition and direct scanning of dc voltages. OPTICS EXPRESS 2023; 31:33787-33798. [PMID: 37859151 DOI: 10.1364/oe.497721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 09/18/2023] [Indexed: 10/21/2023]
Abstract
Excess micromotion is detrimental to accurate qubit control of trapped ions, thus measuring and minimizing it is crucial. In this paper, we present a simple approach for measuring and suppressing excess micromotion of trapped ions by leveraging the existing laser-driven qubit transition scheme combined with direct scanning of dc voltages. The compensation voltage is deduced by analyzing the Bessel expansion of a scanned qubit transition rate. The method provides a fair level of sensitivity for practical quantum computing applications, while demanding minimal deviation of trap condition. By accomplishing compensation of excess micromotion in the qubit momentum-excitation direction, the scheme offers an additional avenue for excess micromotion compensation, complementing existing compensation schemes.
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2
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Leu AD, Gely MF, Weber MA, Smith MC, Nadlinger DP, Lucas DM. Fast, High-Fidelity Addressed Single-Qubit Gates Using Efficient Composite Pulse Sequences. PHYSICAL REVIEW LETTERS 2023; 131:120601. [PMID: 37802949 DOI: 10.1103/physrevlett.131.120601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 08/29/2023] [Indexed: 10/08/2023]
Abstract
We use electronic microwave control methods to implement addressed single-qubit gates with high speed and fidelity, for ^{43}Ca^{+} hyperfine "atomic clock" qubits in a cryogenic (100 K) surface trap. For a single qubit, we benchmark an error of 1.5×10^{-6} per Clifford gate (implemented using 600 ns π/2 pulses). For 2 qubits in the same trap zone (ion separation 5 μm), we use a spatial microwave field gradient, combined with an efficient four-pulse scheme, to implement independent addressed gates. Parallel randomized benchmarking on both qubits yields an average error 3.4×10^{-5} per addressed π/2 gate. The scheme scales theoretically to larger numbers of qubits in a single register.
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Affiliation(s)
- A D Leu
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - M F Gely
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - M A Weber
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - M C Smith
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - D P Nadlinger
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - D M Lucas
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
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3
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Li RR, He R, Cui JM, Chen Y, Ye WR, Chen YL, Huang YF, Li CF, Guo GC. A versatile multi-tone laser system for manipulating atomic qubits based on a fiber Mach-Zehnder modulator and second harmonic generation. OPTICS EXPRESS 2022; 30:30098-30107. [PMID: 36242120 DOI: 10.1364/oe.462737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 07/19/2022] [Indexed: 06/16/2023]
Abstract
Stimulated Raman transition is a fundamental method to coherently manipulate quantum states in different physical systems. Phase-coherent dichromatic radiation fields matching the energy level splitting are the key to realizing stimulated Raman transition. Here we demonstrate a flexible-tuning, spectrum-clean and fiber-compatible method to generate a highly phase-coherent and high-power multi-tone laser. This method features the utilization of a broadband fiber Mach-Zehnder modulator working at carrier suppression condition and second harmonic generation. We generate a multi-tone continuous-wave 532 nm laser with a power of 1.5 Watts and utilize it to manipulate the spin and motional states of a trapped 171Yb+ ion via stimulated Raman transition. For spin state manipulation, we acquire an effective Rabi frequency of 2π × 662.3 kHz. Due to the broad bandwidth of the fiber modulator and nonlinear crystal, the frequency gap between tones can be flexibly tuned. Benefiting from the features above, this method can manipulate 171Yb+ and 137Ba+ simultaneously in the multi-species ion trap and has potential to be widely applied in atomic, molecular and optical physics.
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4
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D'Onofrio M, Xie Y, Rasmusson AJ, Wolanski E, Cui J, Richerme P. Radial Two-Dimensional Ion Crystals in a Linear Paul Trap. PHYSICAL REVIEW LETTERS 2021; 127:020503. [PMID: 34296899 DOI: 10.1103/physrevlett.127.020503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 06/09/2021] [Indexed: 06/13/2023]
Abstract
We experimentally study two-dimensional (2D) Coulomb crystals in the "radial-2D" phase of a linear Paul trap. This phase is identified by a 2D ion lattice aligned entirely with the radial plane and is created by imposing a large ratio of axial to radial trapping potentials. Using arrays of up to 19 ^{171}Yb^{+} ions, we demonstrate that the structural phase boundaries of such crystals are well described by the pseudopotential approximation, despite the time-dependent ion positions driven by intrinsic micromotion. We further observe that micromotion-induced heating of the radial-2D crystal is confined to the radial plane. Finally, we verify that the transverse motional modes, which are used in most ion-trap quantum simulation schemes, are well-predictable numerically and remain decoupled and cold in this geometry. Our results establish radial-2D ion crystals as a robust experimental platform for realizing a variety of theoretical proposals in quantum simulation and computation.
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Affiliation(s)
- Marissa D'Onofrio
- Indiana University Department of Physics, Bloomington, Indiana 47405, USA and Indiana University Quantum Science and Engineering Center, Bloomington, Indiana 47405, USA
| | - Yuanheng Xie
- Indiana University Department of Physics, Bloomington, Indiana 47405, USA and Indiana University Quantum Science and Engineering Center, Bloomington, Indiana 47405, USA
| | - A J Rasmusson
- Indiana University Department of Physics, Bloomington, Indiana 47405, USA and Indiana University Quantum Science and Engineering Center, Bloomington, Indiana 47405, USA
| | - Evangeline Wolanski
- Indiana University Department of Physics, Bloomington, Indiana 47405, USA and Indiana University Quantum Science and Engineering Center, Bloomington, Indiana 47405, USA
| | - Jiafeng Cui
- Indiana University Department of Physics, Bloomington, Indiana 47405, USA and Indiana University Quantum Science and Engineering Center, Bloomington, Indiana 47405, USA
| | - Philip Richerme
- Indiana University Department of Physics, Bloomington, Indiana 47405, USA and Indiana University Quantum Science and Engineering Center, Bloomington, Indiana 47405, USA
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5
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Shinjo A, Baba M, Higashiyama K, Saito R, Mukaiyama T. Three-Dimensional Matter-Wave Interferometry of a Trapped Single Ion. PHYSICAL REVIEW LETTERS 2021; 126:153604. [PMID: 33929227 DOI: 10.1103/physrevlett.126.153604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 02/02/2021] [Accepted: 03/19/2021] [Indexed: 06/12/2023]
Abstract
We report on a demonstration of Ramsey interferometry by three-dimensional motion with a trapped ^{171}Yb^{+} ion. We applied a momentum kick to the ion in a direction diagonal to the trap axes to initiate three-dimensional motion using a mode-locked pulse laser. The interference signal was analyzed theoretically to demonstrate three-dimensional matter-wave interference. This work paves the way to realizing matter-wave interferometry using trapped ions.
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Affiliation(s)
- Ami Shinjo
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Masato Baba
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Koya Higashiyama
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Ryoichi Saito
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
- Quantum Information and Quantum Biology Division, Institute for Open and Transdisciplinary Research Initiatives, Osaka University, Osaka 560-8531, Japan
| | - Takashi Mukaiyama
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
- Quantum Information and Quantum Biology Division, Institute for Open and Transdisciplinary Research Initiatives, Osaka University, Osaka 560-8531, Japan
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6
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Wang P, Luan CY, Qiao M, Um M, Zhang J, Wang Y, Yuan X, Gu M, Zhang J, Kim K. Single ion qubit with estimated coherence time exceeding one hour. Nat Commun 2021; 12:233. [PMID: 33431845 PMCID: PMC7801401 DOI: 10.1038/s41467-020-20330-w] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 11/24/2020] [Indexed: 11/08/2022] Open
Abstract
Realizing a long coherence time quantum memory is a major challenge of current quantum technology. Until now, the longest coherence-time of a single qubit was reported as 660 s in a single 171Yb+ ion-qubit through the technical developments of sympathetic cooling and dynamical decoupling pulses, which addressed heating-induced detection inefficiency and magnetic field fluctuations. However, it was not clear what prohibited further enhancement. Here, we identify and suppress the limiting factors, which are the remaining magnetic-field fluctuations, frequency instability and leakage of the microwave reference-oscillator. Then, we observe the coherence time of around 5500 s for the 171Yb+ ion-qubit, which is the time constant of the exponential decay fit from the measurements up to 960 s. We also systematically study the decoherence process of the quantum memory by using quantum process tomography and analyze the results by applying recently developed resource theories of quantum memory and coherence. Our experimental demonstration will accelerate practical applications of quantum memories for various quantum information processing, especially in the noisy-intermediate-scale quantum regime.
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Affiliation(s)
- Pengfei Wang
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, 100084, Beijing, China.
| | - Chun-Yang Luan
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, 100084, Beijing, China
| | - Mu Qiao
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, 100084, Beijing, China
| | - Mark Um
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, 100084, Beijing, China
| | - Junhua Zhang
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, 100084, Beijing, China
- Shenzhen Institute for Quantum Science and Engineering, and Department of Physics, Southern University of Science and Technology, 518055, Shenzhen, P. R. China
| | - Ye Wang
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, 100084, Beijing, China
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, 27708, USA
| | - Xiao Yuan
- Stanford Institute for Theoretical Physics, Stanford University, Stanford, CA, 94305, USA
- Center on Frontiers of Computing Studies, Department of Computer Science, Peking University, Beijing, 100871, China
| | - Mile Gu
- Centre for Quantum Technologies, National University of Singapore, Singapore, 117543, Singapore
- School of Mathematical and Physical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
- Complexity Institute, Nanyang Technological University, Singapore, 637335, Singapore
| | - Jingning Zhang
- Beijing Academy of Quantum Information Sciences, 100193, Beijing, China
| | - Kihwan Kim
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, 100084, Beijing, China.
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7
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Wang L, Liu M, Yu S, Xu P, He X, Wang K, Wang J, Zhan M. Effect of an echo sequence to a trapped single-atom interferometer with photon momentum kicks. OPTICS EXPRESS 2020; 28:15038-15049. [PMID: 32403537 DOI: 10.1364/oe.385700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 04/15/2020] [Indexed: 06/11/2023]
Abstract
We investigate a single-atom interferometer (SAI) in an optical dipole trap (ODT) with photon momentum kicks. An echo sequence is used for the SAI. We find experimentally that interference visibilities of a counter-propagating Raman type SAI decay much faster than the co-propagating case. To understand the underlying mechanism, a wave-packet propagating simulation is developed for the ODT-guided SAI. We show that in state dependent dipole potentials, the coupling between external dynamics and internal states makes the atom evolve in different paths during the interfering process. The acquired momentum from counter-propagating Raman pulses forces the external motional wave packets of two paths be completely separated and the interferometer visibility decays quickly compared to that of the co-propagating Raman pulses process. Meanwhile, the echo interference visibility experiences revival or instantaneous collapse which depends on the π pulse adding time at approximate integer multiples or half integer multiples of the trap period.
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8
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Liu Y, Tian J, Betzholz R, Cai J. Pulsed Quantum-State Reconstruction of Dark Systems. PHYSICAL REVIEW LETTERS 2019; 122:110406. [PMID: 30951349 DOI: 10.1103/physrevlett.122.110406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Indexed: 06/09/2023]
Abstract
We propose a novel strategy to reconstruct the quantum state of dark systems, i.e., degrees of freedom that are not directly accessible for measurement or control. Our scheme relies on the quantum control of a two-level probe that exerts a state-dependent potential on the dark system. Using a sequence of control pulses applied to the probe makes it possible to tailor the information one can obtain and, for example, allows us to reconstruct the density operator of a dark spin as well as the Wigner characteristic function of a harmonic oscillator. Because of the symmetry of the applied pulse sequence, this scheme is robust against slow noise on the probe. The proof-of-principle experiments are readily feasible in solid-state spins and trapped ions.
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Affiliation(s)
- Yu Liu
- School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
- International Joint Laboratory on Quantum Sensing and Quantum Metrology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Jiazhao Tian
- School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
- International Joint Laboratory on Quantum Sensing and Quantum Metrology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Ralf Betzholz
- School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
- International Joint Laboratory on Quantum Sensing and Quantum Metrology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Jianming Cai
- School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
- International Joint Laboratory on Quantum Sensing and Quantum Metrology, Huazhong University of Science and Technology, Wuhan 430074, China
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9
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Jo H, Song Y, Ahn J. Qubit leakage suppression by ultrafast composite pulses. OPTICS EXPRESS 2019; 27:3944-3951. [PMID: 30876018 DOI: 10.1364/oe.27.003944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 12/24/2018] [Indexed: 06/09/2023]
Abstract
The leakage suppression problem is considered for a three-level ladder-type quantum system, in which the first two levels are the qubit system and the third is the leakage state weakly coupled to the qubit system. We show that two (three) phase- and amplitude-controlled pulses are sufficient for arbitrary qubit controls from the ground (an arbitrary) initial state, with leakage suppressed up to the first order of perturbation without additional pulse-area cost. A proof-of-principle experiment was performed with shaped ultrafast optical pulses and cold rubidium atoms, and the result shows a good agreement with the theory.
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10
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Hess PW, Becker P, Kaplan HB, Kyprianidis A, Lee AC, Neyenhuis B, Pagano G, Richerme P, Senko C, Smith J, Tan WL, Zhang J, Monroe C. Non-thermalization in trapped atomic ion spin chains. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2017; 375:rsta.2017.0107. [PMID: 29084886 PMCID: PMC5665787 DOI: 10.1098/rsta.2017.0107] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 06/27/2017] [Indexed: 05/27/2023]
Abstract
Linear arrays of trapped and laser-cooled atomic ions are a versatile platform for studying strongly interacting many-body quantum systems. Effective spins are encoded in long-lived electronic levels of each ion and made to interact through laser-mediated optical dipole forces. The advantages of experiments with cold trapped ions, including high spatio-temporal resolution, decoupling from the external environment and control over the system Hamiltonian, are used to measure quantum effects not always accessible in natural condensed matter samples. In this review, we highlight recent work using trapped ions to explore a variety of non-ergodic phenomena in long-range interacting spin models, effects that are heralded by the memory of out-of-equilibrium initial conditions. We observe long-lived memory in static magnetizations for quenched many-body localization and prethermalization, while memory is preserved in the periodic oscillations of a driven discrete time crystal state.This article is part of the themed issue 'Breakdown of ergodicity in quantum systems: from solids to synthetic matter'.
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Affiliation(s)
- P W Hess
- Joint Quantum Institute, Department of Physics, University of Maryland and National Institute of Standards and Technology, College Park, MD 20742, USA
| | - P Becker
- Joint Quantum Institute, Department of Physics, University of Maryland and National Institute of Standards and Technology, College Park, MD 20742, USA
| | - H B Kaplan
- Joint Quantum Institute, Department of Physics, University of Maryland and National Institute of Standards and Technology, College Park, MD 20742, USA
| | - A Kyprianidis
- Joint Quantum Institute, Department of Physics, University of Maryland and National Institute of Standards and Technology, College Park, MD 20742, USA
| | - A C Lee
- Joint Quantum Institute, Department of Physics, University of Maryland and National Institute of Standards and Technology, College Park, MD 20742, USA
| | - B Neyenhuis
- Joint Quantum Institute, Department of Physics, University of Maryland and National Institute of Standards and Technology, College Park, MD 20742, USA
| | - G Pagano
- Joint Quantum Institute, Department of Physics, University of Maryland and National Institute of Standards and Technology, College Park, MD 20742, USA
| | - P Richerme
- Joint Quantum Institute, Department of Physics, University of Maryland and National Institute of Standards and Technology, College Park, MD 20742, USA
| | - C Senko
- Joint Quantum Institute, Department of Physics, University of Maryland and National Institute of Standards and Technology, College Park, MD 20742, USA
| | - J Smith
- Joint Quantum Institute, Department of Physics, University of Maryland and National Institute of Standards and Technology, College Park, MD 20742, USA
| | - W L Tan
- Joint Quantum Institute, Department of Physics, University of Maryland and National Institute of Standards and Technology, College Park, MD 20742, USA
| | - J Zhang
- Joint Quantum Institute, Department of Physics, University of Maryland and National Institute of Standards and Technology, College Park, MD 20742, USA
| | - C Monroe
- Joint Quantum Institute, Department of Physics, University of Maryland and National Institute of Standards and Technology, College Park, MD 20742, USA
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11
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Wong-Campos JD, Moses SA, Johnson KG, Monroe C. Demonstration of Two-Atom Entanglement with Ultrafast Optical Pulses. PHYSICAL REVIEW LETTERS 2017; 119:230501. [PMID: 29286704 DOI: 10.1103/physrevlett.119.230501] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Indexed: 06/07/2023]
Abstract
We demonstrate quantum entanglement of two trapped atomic ion qubits using a sequence of ultrafast laser pulses. Unlike previous demonstrations of entanglement mediated by the Coulomb interaction, this scheme does not require confinement to the Lamb-Dicke regime and can be less sensitive to ambient noise due to its speed. To elucidate the physics of an ultrafast phase gate, we generate a high entanglement rate using just ten pulses, each of ∼20 ps duration, and demonstrate an entangled Bell state with (76±1)% fidelity. These results pave the way for entanglement operations within a large collection of qubits by exciting only local modes of motion.
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Affiliation(s)
- J D Wong-Campos
- Joint Quantum Institute, Joint Center for Quantum Information and Computer Science, and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - S A Moses
- Joint Quantum Institute, Joint Center for Quantum Information and Computer Science, and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - K G Johnson
- Joint Quantum Institute, Joint Center for Quantum Information and Computer Science, and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - C Monroe
- Joint Quantum Institute, Joint Center for Quantum Information and Computer Science, and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
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12
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Inlek IV, Crocker C, Lichtman M, Sosnova K, Monroe C. Multispecies Trapped-Ion Node for Quantum Networking. PHYSICAL REVIEW LETTERS 2017; 118:250502. [PMID: 28696766 DOI: 10.1103/physrevlett.118.250502] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Indexed: 06/07/2023]
Abstract
Trapped atomic ions are a leading platform for quantum information networks, with long-lived identical qubit memories that can be locally entangled through their Coulomb interaction and remotely entangled through photonic channels. However, performing both local and remote operations in a single node of a quantum network requires extreme isolation between spectator qubit memories and qubits associated with the photonic interface. We achieve this isolation by cotrapping ^{171}Yb^{+} and ^{138}Ba^{+} qubits. We further demonstrate the ingredients of a scalable ion trap network node with two distinct experiments that consist of entangling the mixed species qubit pair through their collective motion and entangling a ^{138}Ba^{+} qubit with an emitted visible photon.
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Affiliation(s)
- I V Inlek
- Joint Quantum Institute and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - C Crocker
- Joint Quantum Institute and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - M Lichtman
- Joint Quantum Institute and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - K Sosnova
- Joint Quantum Institute and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - C Monroe
- Joint Quantum Institute and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
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13
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A Study on Fast Gates for Large-Scale Quantum Simulation with Trapped Ions. Sci Rep 2017; 7:46197. [PMID: 28401945 PMCID: PMC5388870 DOI: 10.1038/srep46197] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 03/10/2017] [Indexed: 11/08/2022] Open
Abstract
Large-scale digital quantum simulations require thousands of fundamental entangling gates to construct the simulated dynamics. Despite success in a variety of small-scale simulations, quantum information processing platforms have hitherto failed to demonstrate the combination of precise control and scalability required to systematically outmatch classical simulators. We analyse how fast gates could enable trapped-ion quantum processors to achieve the requisite scalability to outperform classical computers without error correction. We analyze the performance of a large-scale digital simulator, and find that fidelity of around 70% is realizable for π-pulse infidelities below 10-5 in traps subject to realistic rates of heating and dephasing. This scalability relies on fast gates: entangling gates faster than the trap period.
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14
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Hussain MI, Petrasiunas MJ, Bentley CDB, Taylor RL, Carvalho ARR, Hope JJ, Streed EW, Lobino M, Kielpinski D. Ultrafast, high repetition rate, ultraviolet, fiber-laser-based source: application towards Yb + fast quantum-logic. OPTICS EXPRESS 2016; 24:16638-16648. [PMID: 27464118 DOI: 10.1364/oe.24.016638] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Trapped ions are one of the most promising approaches for the realization of a universal quantum computer. Faster quantum logic gates could dramatically improve the performance of trapped-ion quantum computers, and require the development of suitable high repetition rate pulsed lasers. Here we report on a robust frequency upconverted fiber laser based source, able to deliver 2.5 ps ultraviolet (UV) pulses at a stabilized repetition rate of 300.00000 MHz with an average power of 190 mW. The laser wavelength is resonant with the strong transition in Ytterbium (Yb+) at 369.53 nm and its repetition rate can be scaled up using high harmonic mode locking. We show that our source can produce arbitrary pulse patterns using a programmable pulse pattern generator and fast modulating components. Finally, simulations demonstrate that our laser is capable of performing resonant, temperature-insensitive, two-qubit quantum logic gates on trapped Yb+ ions faster than the trap period and with fidelity above 99%.
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15
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Generation of large coherent states by bang-bang control of a trapped-ion oscillator. Nat Commun 2016; 7:11243. [PMID: 27046513 PMCID: PMC4822070 DOI: 10.1038/ncomms11243] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 03/03/2016] [Indexed: 11/20/2022] Open
Abstract
Fast control of quantum systems is essential to make use of quantum properties before they degrade by decoherence. This is important for quantum-enhanced information processing, as well as for pushing quantum systems towards the boundary between quantum and classical physics. ‘Bang–bang' control attains the ultimate speed limit by making large changes to control fields much faster than the system can respond, but is often challenging to implement experimentally. Here we demonstrate bang–bang control of a trapped-ion oscillator using nanosecond switching of the trapping potentials. We perform controlled displacements with which we realize coherent states with up to 10,000 quanta of energy. We use these displaced states to verify the form of the ion-light interaction at high excitations far outside the usual regime of operation. These methods provide new possibilities for quantum-state manipulation and generation, alongside the potential for a significant increase in operational clock speed for trapped-ion quantum information processing. Fast control of quantum systems is essential to exploit their properties for information processing before they are lost to decoherence. Here the authors demonstrate the use of quasi instantaneous changes to the trapping potential of a trapped-ion to create highly-excited quantum coherent states.
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16
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Johnson KG, Neyenhuis B, Mizrahi J, Wong-Campos JD, Monroe C. Sensing Atomic Motion from the Zero Point to Room Temperature with Ultrafast Atom Interferometry. PHYSICAL REVIEW LETTERS 2015; 115:213001. [PMID: 26636850 DOI: 10.1103/physrevlett.115.213001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Indexed: 06/05/2023]
Abstract
We sense the motion of a trapped atomic ion using a sequence of state-dependent ultrafast momentum kicks. We use this atom interferometer to characterize a nearly pure quantum state with n=1 phonon and accurately measure thermal states ranging from near the zero-point energy to n[over ¯]~10^{4}, with the possibility of extending at least 100 times higher in energy. The complete energy range of this method spans from the ground state to far outside of the Lamb-Dicke regime, where atomic motion is greater than the optical wavelength. Apart from thermometry, these interferometric techniques are useful for characterizing ultrafast entangling gates between multiple trapped ions.
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Affiliation(s)
- K G Johnson
- Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA
| | - B Neyenhuis
- Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA
| | - J Mizrahi
- Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA
| | - J D Wong-Campos
- Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA
| | - C Monroe
- Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA
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17
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Affiliation(s)
- Lilian Childress
- Physics Department, McGill University, Montreal, Quebec H3A 2T8, Canada
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18
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Lim J, Lee HG, Lee S, Park CY, Ahn J. Ultrafast Ramsey interferometry to implement cold atomic qubit gates. Sci Rep 2014; 4:5867. [PMID: 25070166 PMCID: PMC5376194 DOI: 10.1038/srep05867] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 07/04/2014] [Indexed: 11/25/2022] Open
Abstract
Quantum computing is based on unitary operations in a two-level quantum system, a qubit, as the fundamental building block, and the ability to perform qubit operations in an amount of time that is considerably shorter than the coherence time is an essential requirement for quantum computation. Here, we present an experimental demonstration of arbitrary single-qubit SU(2) quantum gate operations achieved at a terahertz clock speed. Implemented by coherent control methods of tailored ultrafast laser interaction with cold rubidium atomic qubits, Bloch vector manipulation about all three rotational axes was successfully demonstrated. The dynamic evolution of the qubits was successfully measured by devised femtosecond Ramsey interferometry. We anticipate this demonstration to be a starting point to process quantum algorithm in a simplified manner by a programmed sequence of femtosecond laser pulses.
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Affiliation(s)
- Jongseok Lim
- Department of Physics, KAIST, Daejeon 305-701, Korea
- Current address: Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - Han-gyeol Lee
- Department of Physics, KAIST, Daejeon 305-701, Korea
| | - Sangkyung Lee
- Korea Research Institute of Standards and Science, Daejeon 305-340, Korea
| | - Chang-Yong Park
- Korea Research Institute of Standards and Science, Daejeon 305-340, Korea
| | - Jaewook Ahn
- Department of Physics, KAIST, Daejeon 305-701, Korea
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19
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Muralidharan S, Kim J, Lütkenhaus N, Lukin MD, Jiang L. Ultrafast and fault-tolerant quantum communication across long distances. PHYSICAL REVIEW LETTERS 2014; 112:250501. [PMID: 25014798 DOI: 10.1103/physrevlett.112.250501] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Indexed: 06/03/2023]
Abstract
Quantum repeaters (QRs) provide a way of enabling long distance quantum communication by establishing entangled qubits between remote locations. In this Letter, we investigate a new approach to QRs in which quantum information can be faithfully transmitted via a noisy channel without the use of long distance teleportation, thus eliminating the need to establish remote entangled links. Our approach makes use of small encoding blocks to fault-tolerantly correct both operational and photon loss errors. We describe a way to optimize the resource requirement for these QRs with the aim of the generation of a secure key. Numerical calculations indicate that the number of quantum memory bits at each repeater station required for the generation of one secure key has favorable polylogarithmic scaling with the distance across which the communication is desired.
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Affiliation(s)
- Sreraman Muralidharan
- Department of Electrical Engineering, Yale University, New Haven, Connecticut 06511, USA
| | - Jungsang Kim
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Norbert Lütkenhaus
- Institute of Quantum computing, University of Waterloo, N2L 3G1 Waterloo, Canada
| | - Mikhail D Lukin
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Liang Jiang
- Department of Applied Physics, Yale University, New Haven, Connecticut 06511, USA
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20
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Choi T, Debnath S, Manning TA, Figgatt C, Gong ZX, Duan LM, Monroe C. Optimal quantum control of multimode couplings between trapped ion qubits for scalable entanglement. PHYSICAL REVIEW LETTERS 2014; 112:190502. [PMID: 24877921 DOI: 10.1103/physrevlett.112.190502] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Indexed: 06/03/2023]
Abstract
We demonstrate entangling quantum gates within a chain of five trapped ion qubits by optimally shaping optical fields that couple to multiple collective modes of motion. We individually address qubits with segmented optical pulses to construct multipartite entangled states in a programmable way. This approach enables high-fidelity gates that can be scaled to larger qubit registers for quantum computation and simulation.
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Affiliation(s)
- T Choi
- Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA
| | - S Debnath
- Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA
| | - T A Manning
- Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA
| | - C Figgatt
- Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA
| | - Z-X Gong
- Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA and Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - L-M Duan
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - C Monroe
- Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA
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21
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Cadarso A, Mur-Petit J, García-Ripoll JJ. Phase stabilization of a frequency comb using multipulse quantum interferometry. PHYSICAL REVIEW LETTERS 2014; 112:073603. [PMID: 24579598 DOI: 10.1103/physrevlett.112.073603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Indexed: 06/03/2023]
Abstract
From the interaction between a frequency comb and an atomic qubit, we derive quantum protocols for the determination of the carrier-envelope offset phase, using the qubit coherence as a reference, and without the need of frequency doubling or an octave spanning comb. Compared with a trivial interference protocol, the multipulse protocol results in a polynomial enhancement of the sensitivity O(N-2) with the number N of laser pulses involved. We specialize the protocols using optical or hyperfine qubits, Λ schemes, and Raman transitions, and introduce methods where the reference is another phase-stable cw laser or frequency comb.
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Affiliation(s)
- Andrea Cadarso
- Instituto de Física Fundamental, IFF-CSIC, Serrano 113 b, Madrid 28006, Spain and Departamento de Análisis Matemático, Universidad Complutense de Madrid, 24040 Madrid, Spain
| | - Jordi Mur-Petit
- Instituto de Física Fundamental, IFF-CSIC, Serrano 113 b, Madrid 28006, Spain and Instituto de Estructura de la Materia, IEM-CSIC, Serrano 123, Madrid 28006, Spain
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22
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Gamouras A, Mathew R, Freisem S, Deppe DG, Hall KC. Simultaneous deterministic control of distant qubits in two semiconductor quantum dots. NANO LETTERS 2013; 13:4666-4670. [PMID: 24001027 DOI: 10.1021/nl4018176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In optimal quantum control (OQC), a target quantum state of matter is achieved by tailoring the phase and amplitude of the control Hamiltonian through femtosecond pulse-shaping techniques and powerful adaptive feedback algorithms. Motivated by recent applications of OQC in quantum information science as an approach to optimizing quantum gates in atomic and molecular systems, here we report the experimental implementation of OQC in a solid-state system consisting of distinguishable semiconductor quantum dots. We demonstrate simultaneous high-fidelity π and 2π single qubit gates in two different quantum dots using a single engineered infrared femtosecond pulse. These experiments enhance the scalability of semiconductor-based quantum hardware and lay the foundation for applications of pulse shaping to optimize quantum gates in other solid-state systems.
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Affiliation(s)
- A Gamouras
- Department of Physics and Atmospheric Science, Dalhousie University , Halifax, Nova Scotia B3H4R2, Canada
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23
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Richerme P, Senko C, Korenblit S, Smith J, Lee A, Islam R, Campbell WC, Monroe C. Quantum catalysis of magnetic phase transitions in a quantum simulator. PHYSICAL REVIEW LETTERS 2013; 111:100506. [PMID: 25166645 DOI: 10.1103/physrevlett.111.100506] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 06/25/2013] [Indexed: 06/03/2023]
Abstract
We control quantum fluctuations to create the ground state magnetic phases of a classical Ising model with a tunable longitudinal magnetic field using a system of 6 to 10 atomic ion spins. Because of the long-range Ising interactions, the various ground state spin configurations are separated by multiple first-order phase transitions, which in our zero temperature system cannot be driven by thermal fluctuations. We instead use a transverse magnetic field as a quantum catalyst to observe the first steps of the complete fractal devil's staircase, which emerges in the thermodynamic limit and can be mapped to a large number of many-body and energy-optimization problems.
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Affiliation(s)
- P Richerme
- Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA
| | - C Senko
- Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA
| | - S Korenblit
- Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA
| | - J Smith
- Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA
| | - A Lee
- Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA
| | - R Islam
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - W C Campbell
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
| | - C Monroe
- Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA
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24
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Mizrahi J, Senko C, Neyenhuis B, Johnson KG, Campbell WC, Conover CWS, Monroe C. Ultrafast spin-motion entanglement and interferometry with a single atom. PHYSICAL REVIEW LETTERS 2013; 110:203001. [PMID: 25167401 DOI: 10.1103/physrevlett.110.203001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Indexed: 06/03/2023]
Abstract
We report entanglement of a single atom's hyperfine spin state with its motional state in a time scale of less than 3 ns. We engineer a short train of intense laser pulses to impart a spin-dependent momentum transfer of ± 2 ħk. Using pairs of momentum kicks, we create an atomic interferometer and demonstrate collapse and revival of spin coherence as the motional wave packet is split and recombined. The revival after a pair of kicks occurs only when the second kick is delayed by an integer multiple of the harmonic trap period, a signature of entanglement and disentanglement of the spin with the motion. Such quantum control opens a new regime of ultrafast entanglement in atomic qubits.
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Affiliation(s)
- J Mizrahi
- Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA
| | - C Senko
- Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA
| | - B Neyenhuis
- Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA
| | - K G Johnson
- Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA
| | - W C Campbell
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA
| | - C W S Conover
- Physics Department, Colby College, Waterville, Maine 04901, USA
| | - C Monroe
- Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA
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25
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Islam R, Senko C, Campbell WC, Korenblit S, Smith J, Lee A, Edwards EE, Wang CCJ, Freericks JK, Monroe C. Emergence and Frustration of Magnetism with Variable-Range Interactions in a Quantum Simulator. Science 2013; 340:583-7. [DOI: 10.1126/science.1232296] [Citation(s) in RCA: 315] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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26
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Lim J, Lee K, Ahn J. Ultrafast Rabi flopping in a three-level energy ladder. OPTICS LETTERS 2012; 37:3378-3380. [PMID: 23381263 DOI: 10.1364/ol.37.003378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We demonstrate Rabi oscillation of a resonant two-photon transition in a three-level ladder-type quantum system of gaseous rubidium atoms induced by a single femtosecond laser pulse. For this, we shape the flat-top spatial profile of the laser pulse and perform the ultrafast population cycling of the atoms as a function of pulse energy. The experimental result confirms that the Rabi frequency of the transition from a ground state to a final state depends linearly on the pulse area, although the transition is a two-photon process.
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Affiliation(s)
- Jongseok Lim
- Department of Physics, KAIST, Daejeon 305-701, South Korea
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27
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Hayes D, Clark SM, Debnath S, Hucul D, Inlek IV, Lee KW, Quraishi Q, Monroe C. Coherent error suppression in multiqubit entangling gates. PHYSICAL REVIEW LETTERS 2012; 109:020503. [PMID: 23030141 DOI: 10.1103/physrevlett.109.020503] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Revised: 04/26/2012] [Indexed: 06/01/2023]
Abstract
We demonstrate a simple pulse shaping technique designed to improve the fidelity of spin-dependent force operations commonly used to implement entangling gates in trapped ion systems. This extension of the Mølmer-Sørensen gate can theoretically suppress the effects of certain frequency and timing errors to any desired order and is demonstrated through Walsh modulation of a two qubit entangling gate on trapped atomic ions. The technique is applicable to any system of qubits coupled through collective harmonic oscillator modes.
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Affiliation(s)
- D Hayes
- Joint Quantum Institute and Department of Physics, University of Maryland, College Park, Maryland 20742, USA.
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28
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Schowalter SJ, Chen K, Rellergert WG, Sullivan ST, Hudson ER. An integrated ion trap and time-of-flight mass spectrometer for chemical and photo- reaction dynamics studies. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:043103. [PMID: 22559511 DOI: 10.1063/1.3700216] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We demonstrate the integration of a linear quadrupole trap with a simple time-of-flight mass spectrometer with medium-mass resolution (m/Δm ∼ 50) geared towards the demands of atomic, molecular, and chemical physics experiments. By utilizing a novel radial ion extraction scheme from the linear quadrupole trap into the mass analyzer, a device with large trap capacity and high optical access is realized without sacrificing mass resolution. This provides the ability to address trapped ions with laser light and facilitates interactions with neutral background gases prior to analyzing the trapped ions. Here, we describe the construction and implementation of the device as well as present representative ToF spectra. We conclude by demonstrating the flexibility of the device with proof-of-principle experiments that include the observation of molecular-ion photodissociation and the measurement of trapped-ion chemical reaction rates.
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Affiliation(s)
- Steven J Schowalter
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA.
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29
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Romero G, Ballester D, Wang YM, Scarani V, Solano E. Ultrafast quantum gates in circuit QED. PHYSICAL REVIEW LETTERS 2012; 108:120501. [PMID: 22540561 DOI: 10.1103/physrevlett.108.120501] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Indexed: 05/10/2023]
Abstract
We present a method to implement ultrafast two-qubit gates valid for the ultrastrong coupling and deep strong coupling regimes of light-matter interaction, considering state-of-the-art circuit quantum electrodynamics technology. Our proposal includes a suitable qubit architecture and is based on a four-step sequential displacement of the intracavity field, operating at a time proportional to the inverse of the resonator frequency. Through ab initio calculations, we show that these quantum gates can be performed at subnanosecond time scales while keeping a fidelity above 99%.
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Affiliation(s)
- G Romero
- Departamento de Química Física, Universidad del País Vasco UPV/EHU, Apartado 644, 48080 Bilbao, Spain
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30
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Ospelkaus C, Warring U, Colombe Y, Brown KR, Amini JM, Leibfried D, Wineland DJ. Microwave quantum logic gates for trapped ions. Nature 2011; 476:181-4. [DOI: 10.1038/nature10290] [Citation(s) in RCA: 233] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Accepted: 06/14/2011] [Indexed: 11/09/2022]
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31
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Onset of a quantum phase transition with a trapped ion quantum simulator. Nat Commun 2011; 2:377. [PMID: 21730958 DOI: 10.1038/ncomms1374] [Citation(s) in RCA: 294] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Accepted: 06/02/2011] [Indexed: 11/08/2022] Open
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32
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Biercuk MJ, Uys H, Britton JW, Vandevender AP, Bollinger JJ. Phase-coherent detection of an optical dipole force by Doppler velocimetry. OPTICS EXPRESS 2011; 19:10304-10316. [PMID: 21643288 DOI: 10.1364/oe.19.010304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We report phase-coherent Doppler detection of optical dipole forces using large ion crystals in a Penning trap. The technique is based on laser Doppler velocimetry using a cycling transition in 9Be+ near 313 nm and the center-of-mass (COM) ion motional mode. The optical dipole force is tuned to excite the COM mode, and measurements of photon arrival times synchronized with the excitation potential show oscillations with a period commensurate with the COM motional frequency. Experimental results compare well with a quantitative model for a driven harmonic oscillator. This technique permits characterization of motional modes in ion crystals; the measurement of both frequency and phase information relative to the driving force is a key enabling capability--comparable to lockin detection - providing access to a parameter that is typically not available in time-averaged measurements. This additional information facilitates discrimination of nearly degenerate motional modes.
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Affiliation(s)
- M J Biercuk
- National Institute of Standards and Technology, Ion Storage Group, Boulder, CO 80305, USA.
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33
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Casanova J, Romero G, Lizuain I, García-Ripoll JJ, Solano E. Deep strong coupling regime of the Jaynes-Cummings model. PHYSICAL REVIEW LETTERS 2010; 105:263603. [PMID: 21231661 DOI: 10.1103/physrevlett.105.263603] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Indexed: 05/30/2023]
Abstract
We study the quantum dynamics of a two-level system interacting with a quantized harmonic oscillator in the deep strong coupling regime (DSC) of the Jaynes-Cummings model, that is, when the coupling strength g is comparable or larger than the oscillator frequency ω (g/ω≳1). In this case, the rotating-wave approximation cannot be applied or treated perturbatively in general. We propose an intuitive and predictive physical frame to describe the DSC regime where photon number wave packets bounce back and forth along parity chains of the Hilbert space, while producing collapse and revivals of the initial population. We exemplify our physical frame with numerical and analytical considerations in the qubit population, photon statistics, and Wigner phase space.
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Affiliation(s)
- J Casanova
- Departamento de Química Física, Universidad del País Vasco-Euskal Herriko Unibertsitatea, Bilbao, Spain
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