1
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Lysne NK, Niedermeyer JF, Wilson AC, Slichter DH, Leibfried D. Individual Addressing and State Readout of Trapped Ions Utilizing Radio-Frequency Micromotion. PHYSICAL REVIEW LETTERS 2024; 133:033201. [PMID: 39094141 DOI: 10.1103/physrevlett.133.033201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 05/20/2024] [Indexed: 08/04/2024]
Abstract
Excess "micromotion" of trapped ions due to the residual radio-frequency (rf) trapping field at their location is often undesirable and is usually carefully minimized. Here, we induce precise amounts of excess micromotion on individual ions by adjusting the local static electric field they experience. Micromotion modulates the coupling of an ion to laser fields, ideally tuning it from its maximum value to zero as the ion is moved away from the trap's rf null. We use tunable micromotion to vary the Rabi frequency of stimulated Raman transitions over two orders of magnitude, and to individually control the rates of resonant fluorescence from three ions under global laser illumination without any changes to the driving light fields. The technique is amenable to situations where addressing individual ions with focused laser beams is challenging, such as tightly packed linear ion strings or two-dimensional ion arrays illuminated from the side.
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2
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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 PMCID: PMC11165722 DOI: 10.1038/s41586-021-03809-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Grants] [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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3
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Bardin JC, Slichter DH, Reilly DJ. Microwaves in Quantum Computing. IEEE JOURNAL OF MICROWAVES 2021; 1:10.1109/JMW.2020.3034071. [PMID: 34355217 PMCID: PMC8335598 DOI: 10.1109/jmw.2020.3034071] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Quantum information processing systems rely on a broad range of microwave technologies and have spurred development of microwave devices and methods in new operating regimes. Here we review the use of microwave signals and systems in quantum computing, with specific reference to three leading quantum computing platforms: trapped atomic ion qubits, spin qubits in semiconductors, and superconducting qubits. We highlight some key results and progress in quantum computing achieved through the use of microwave systems, and discuss how quantum computing applications have pushed the frontiers of microwave technology in some areas. We also describe open microwave engineering challenges for the construction of large-scale, fault-tolerant quantum computers.
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Affiliation(s)
- Joseph C Bardin
- Department of Electrical and Computer Engineering, University of Massachusetts Amherst, Amherst, MA 01003 USA
- Google LLC, Goleta, CA 93117 USA
| | - Daniel H Slichter
- Time and Frequency Division, National Institute of Standards and Technology, Boulder, CO 80305 USA
| | - David J Reilly
- Microsoft Inc., Microsoft Quantum Sydney, The University of Sydney, Sydney, NSW 2050, Australia
- ARC Centre of Excellence for Engineered Quantum Systems (EQuS), School of Physics, The University of Sydney, Sydney, NSW 2050, Australia
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4
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Mills M, Wu H, Reed EC, Qi L, Brown KR, Schneider C, Heaven MC, Campbell WC, Hudson ER. Dipole-phonon quantum logic with alkaline-earth monoxide and monosulfide cations. Phys Chem Chem Phys 2020; 22:24964-24973. [PMID: 33140766 DOI: 10.1039/d0cp04574h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Dipole-phonon quantum logic (DPQL) leverages the interaction between polar molecular ions and the motional modes of a trapped-ion Coulomb crystal to provide a potentially scalable route to quantum information science. Here, we study a class of candidate molecular ions for DPQL, the cationic alkaline-earth monoxides and monosulfides, which possess suitable structure for DPQL and can be produced in existing atomic ion experiments with little additional complexity. We present calculations of DPQL operations for one of these molecules, CaO+, and discuss progress towards experimental realization. We also further develop the theory of DPQL to include state preparation and measurement and entanglement of multiple molecular ions.
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Affiliation(s)
- Michael Mills
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA.
| | - Hao Wu
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA.
| | - Evan C Reed
- Departments of Electrical and Computer Engineering, Chemistry, and Physics, Duke University, Durham, North Carolina 27708, USA
| | - Lu Qi
- Departments of Electrical and Computer Engineering, Chemistry, and Physics, Duke University, Durham, North Carolina 27708, USA
| | - Kenneth R Brown
- Departments of Electrical and Computer Engineering, Chemistry, and Physics, Duke University, Durham, North Carolina 27708, USA
| | - Christian Schneider
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA.
| | - Michael C Heaven
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA
| | - Wesley C Campbell
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA. and Center for Quantum Science and Engineering, University of California, Los Angeles, California 90095, USA
| | - Eric R Hudson
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA. and Center for Quantum Science and Engineering, University of California, Los Angeles, California 90095, USA
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5
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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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6
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Higgins G, Pokorny F, Zhang C, Hennrich M. Highly Polarizable Rydberg Ion in a Paul Trap. PHYSICAL REVIEW LETTERS 2019; 123:153602. [PMID: 31702307 DOI: 10.1103/physrevlett.123.153602] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Indexed: 06/10/2023]
Abstract
Usually the influence of the quadratic Stark effect on an ion's trapping potential is minuscule and only needs to be considered in atomic clock experiments. In this work we excite a trapped ion to a Rydberg state with polarizability ∼8 orders of magnitude higher than a low-lying electronic state; we find that the highly polarizable ion experiences a vastly different trapping potential owing to the Stark effect. We observe changes in trap stiffness, equilibrium position, and minimum potential, which can be tuned using the trapping electric fields. These effects lie at the heart of several proposed studies, including a high-fidelity submicrosecond entangling operation; in addition we demonstrate these effects may be used to minimize ion micromotion. Mitigation of Stark effects is important for coherent control of Rydberg ions; we illustrate this by carrying out the first Rabi oscillations between a low-lying electronic state and a Rydberg state of an ion.
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Affiliation(s)
- Gerard Higgins
- Department of Physics, Stockholm University, SE-106 91 Stockholm, Sweden
- Institut für Experimentalphysik, Universität Innsbruck, AT-6020 Innsbruck, Austria
| | - Fabian Pokorny
- Department of Physics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Chi Zhang
- Department of Physics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Markus Hennrich
- Department of Physics, Stockholm University, SE-106 91 Stockholm, Sweden
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7
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Srinivas R, Burd SC, Sutherland RT, Wilson AC, Wineland DJ, Leibfried D, Allcock DTC, Slichter DH. Trapped-Ion Spin-Motion Coupling with Microwaves and a Near-Motional Oscillating Magnetic Field Gradient. PHYSICAL REVIEW LETTERS 2019; 122:163201. [PMID: 31075007 PMCID: PMC6662926 DOI: 10.1103/physrevlett.122.163201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Indexed: 06/09/2023]
Abstract
We present a new method of spin-motion coupling for trapped ions using microwaves and a magnetic field gradient oscillating close to the ions' motional frequency. We demonstrate and characterize this coupling experimentally using a single ion in a surface-electrode trap that incorporates current-carrying electrodes to generate the microwave field and the oscillating magnetic field gradient. Using this method, we perform resolved-sideband cooling of a single motional mode to its ground state.
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Affiliation(s)
- R. Srinivas
- Time and Frequency Division, National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - S. C. Burd
- Time and Frequency Division, National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - R. T. Sutherland
- Physics Division, Physical and Life Sciences, Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - A. C. Wilson
- Time and Frequency Division, National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - D. J. Wineland
- Time and Frequency Division, National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
- Department of Physics, University of Oregon, Eugene, Oregon 97403, USA
| | - D. Leibfried
- Time and Frequency Division, National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - D. T. C. Allcock
- Time and Frequency Division, National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
- Department of Physics, University of Oregon, Eugene, Oregon 97403, USA
| | - D. H. Slichter
- Time and Frequency Division, National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
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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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Ejtemaee S, Haljan PC. 3D Sisyphus Cooling of Trapped Ions. PHYSICAL REVIEW LETTERS 2017; 119:043001. [PMID: 29341732 DOI: 10.1103/physrevlett.119.043001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Indexed: 06/07/2023]
Abstract
Using a laser polarization gradient, we realize 3D Sisyphus cooling of ^{171}Yb^{+} ions confined in and near the Lamb-Dicke regime in a linear Paul trap. The cooling rate and final mean motional energy of a single ion are characterized as a function of laser intensity and compared to semiclassical and quantum simulations. Sisyphus cooling is also applied to a linear string of four ions to obtain a mean energy of 1-3 quanta for all vibrational modes, an approximately order of magnitude reduction below Doppler cooled energies. This is used to enable subsequent, efficient sideband laser cooling.
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Affiliation(s)
- S Ejtemaee
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada
| | - P C Haljan
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada
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10
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Slichter DH, Verma VB, Leibfried D, Mirin RP, Nam SW, Wineland DJ. UV-sensitive superconducting nanowire single photon detectors for integration in an ion trap. OPTICS EXPRESS 2017; 25:8705-8720. [PMID: 28437948 DOI: 10.1364/oe.25.008705] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We demonstrate superconducting nanowire single photon detectors with 76 ± 4% system detection efficiency at a wavelength of 315 nm and an operating temperature of 3.2 K, with a background count rate below 1 count per second at saturated detection efficiency. We propose integrating these detectors into planar surface electrode radio-frequency Paul traps for use in trapped ion quantum information processing. We operate detectors integrated into test ion trap structures at 3.8 K both with and without typical radio-frequency trapping electric fields. The trapping fields reduce system detection efficiency by 9%, but do not increase background count rates.
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11
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Robens C, Zopes J, Alt W, Brakhane S, Meschede D, Alberti A. Low-Entropy States of Neutral Atoms in Polarization-Synthesized Optical Lattices. PHYSICAL REVIEW LETTERS 2017; 118:065302. [PMID: 28234497 DOI: 10.1103/physrevlett.118.065302] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Indexed: 06/06/2023]
Abstract
We create low-entropy states of neutral atoms by utilizing a conceptually new optical-lattice technique that relies on a high-precision, high-bandwidth synthesis of light polarization. Polarization-synthesized optical lattices provide two fully controllable optical lattice potentials, each of them confining only atoms in either one of the two long-lived hyperfine states. By employing one lattice as the storage register and the other one as the shift register, we provide a proof of concept using four atoms that selected regions of the periodic potential can be filled with one particle per site. We expect that our results can be scaled up to thousands of atoms by employing an atom-sorting algorithm with logarithmic complexity, which is enabled by polarization-synthesized optical lattices. Vibrational entropy is subsequently removed by sideband cooling methods. Our results pave the way for a bottom-up approach to creating ultralow-entropy states of a many-body system.
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Affiliation(s)
- Carsten Robens
- Institut für Angewandte Physik, Universität Bonn, Wegelerstrasse 8, D-53115 Bonn, Germany
| | - Jonathan Zopes
- Institut für Angewandte Physik, Universität Bonn, Wegelerstrasse 8, D-53115 Bonn, Germany
| | - Wolfgang Alt
- Institut für Angewandte Physik, Universität Bonn, Wegelerstrasse 8, D-53115 Bonn, Germany
| | - Stefan Brakhane
- Institut für Angewandte Physik, Universität Bonn, Wegelerstrasse 8, D-53115 Bonn, Germany
| | - Dieter Meschede
- Institut für Angewandte Physik, Universität Bonn, Wegelerstrasse 8, D-53115 Bonn, Germany
| | - Andrea Alberti
- Institut für Angewandte Physik, Universität Bonn, Wegelerstrasse 8, D-53115 Bonn, Germany
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12
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Piltz C, Sriarunothai T, Ivanov SS, Wölk S, Wunderlich C. Versatile microwave-driven trapped ion spin system for quantum information processing. SCIENCE ADVANCES 2016; 2:e1600093. [PMID: 27419233 PMCID: PMC4942346 DOI: 10.1126/sciadv.1600093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 06/14/2016] [Indexed: 05/11/2023]
Abstract
Using trapped atomic ions, we demonstrate a tailored and versatile effective spin system suitable for quantum simulations and universal quantum computation. By simply applying microwave pulses, selected spins can be decoupled from the remaining system and, thus, can serve as a quantum memory, while simultaneously, other coupled spins perform conditional quantum dynamics. Also, microwave pulses can change the sign of spin-spin couplings, as well as their effective strength, even during the course of a quantum algorithm. Taking advantage of the simultaneous long-range coupling between three spins, a coherent quantum Fourier transform-an essential building block for many quantum algorithms-is efficiently realized. This approach, which is based on microwave-driven trapped ions and is complementary to laser-based methods, opens a new route to overcoming technical and physical challenges in the quest for a quantum simulator and a quantum computer.
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Affiliation(s)
- Christian Piltz
- Department Physik, Naturwissenschaftlich-Technische Fakultät, Universität Siegen, 57068 Siegen, Germany
| | - Theeraphot Sriarunothai
- Department Physik, Naturwissenschaftlich-Technische Fakultät, Universität Siegen, 57068 Siegen, Germany
| | - Svetoslav S. Ivanov
- Department of Physics, Sofia University, 5 James Bourchier Boulevard, 1164 Sofia, Bulgaria
| | - Sabine Wölk
- Department Physik, Naturwissenschaftlich-Technische Fakultät, Universität Siegen, 57068 Siegen, Germany
| | - Christof Wunderlich
- Department Physik, Naturwissenschaftlich-Technische Fakultät, Universität Siegen, 57068 Siegen, Germany
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13
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Xia T, Lichtman M, Maller K, Carr AW, Piotrowicz MJ, Isenhower L, Saffman M. Randomized benchmarking of single-qubit gates in a 2D array of neutral-atom qubits. PHYSICAL REVIEW LETTERS 2015; 114:100503. [PMID: 25815916 DOI: 10.1103/physrevlett.114.100503] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Indexed: 06/04/2023]
Abstract
We characterize single-qubit Clifford gate operations with randomized benchmarking in a 2D array of neutral-atom qubits and demonstrate global and site selected gates with high fidelity. An average fidelity of F2=0.9983(14) is measured for global microwave-driven gates applied to a 49-qubit array. Single-site gates are implemented with a focused laser beam to Stark shift the microwaves into resonance at a selected site. At Stark selected single sites we observe F2=0.9923(7) and an average spin-flip crosstalk error at other sites of 0.002(9).
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Affiliation(s)
- T Xia
- Department of Physics, University of Wisconsin, 1150 University Avenue, Madison, Wisconsin 53706, USA
| | - M Lichtman
- Department of Physics, University of Wisconsin, 1150 University Avenue, Madison, Wisconsin 53706, USA
| | - K Maller
- Department of Physics, University of Wisconsin, 1150 University Avenue, Madison, Wisconsin 53706, USA
| | - A W Carr
- Department of Physics, University of Wisconsin, 1150 University Avenue, Madison, Wisconsin 53706, USA
| | - M J Piotrowicz
- Department of Physics, University of Wisconsin, 1150 University Avenue, Madison, Wisconsin 53706, USA
| | - L Isenhower
- Department of Physics, University of Wisconsin, 1150 University Avenue, Madison, Wisconsin 53706, USA
| | - M Saffman
- Department of Physics, University of Wisconsin, 1150 University Avenue, Madison, Wisconsin 53706, USA
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14
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Piltz C, Sriarunothai T, Varón AF, Wunderlich C. A trapped-ion-based quantum byte with 10(-5) next-neighbour cross-talk. Nat Commun 2014; 5:4679. [PMID: 25134465 DOI: 10.1038/ncomms5679] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 07/14/2014] [Indexed: 11/09/2022] Open
Abstract
The addressing of a particular qubit within a quantum register is a key pre-requisite for scalable quantum computing. In general, executing a quantum gate with a single qubit, or a subset of qubits, affects the quantum states of all other qubits. This reduced fidelity of the whole-quantum register could prevent the application of quantum error correction protocols and thus preclude scalability. Here we demonstrate addressing of individual qubits within a quantum byte (eight qubits) and measure the error induced in all non-addressed qubits (cross-talk) associated with the application of single-qubit gates. The quantum byte is implemented using microwave-driven hyperfine qubits of (171)Yb(+) ions confined in a Paul trap augmented with a magnetic gradient field. The measured cross-talk is on the order of 10(-5) and therefore below the threshold commonly agreed sufficient to efficiently realize fault-tolerant quantum computing. Hence, our results demonstrate how this threshold can be overcome with respect to cross-talk.
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Affiliation(s)
- C Piltz
- Department Physik, Naturwissenschaftlich-Technische Fakultät, Universität Siegen, 57068 Siegen, Germany
| | - T Sriarunothai
- Department Physik, Naturwissenschaftlich-Technische Fakultät, Universität Siegen, 57068 Siegen, Germany
| | - A F Varón
- Department Physik, Naturwissenschaftlich-Technische Fakultät, Universität Siegen, 57068 Siegen, Germany
| | - C Wunderlich
- Department Physik, Naturwissenschaftlich-Technische Fakultät, Universität Siegen, 57068 Siegen, Germany
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15
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Ding S, Loh H, Hablutzel R, Gao M, Maslennikov G, Matsukevich D. Microwave control of trapped-ion motion assisted by a running optical lattice. PHYSICAL REVIEW LETTERS 2014; 113:073002. [PMID: 25170703 DOI: 10.1103/physrevlett.113.073002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Indexed: 06/03/2023]
Abstract
We experimentally demonstrate microwave control of the motional state of a trapped ion placed in a state-dependent potential generated by a running optical lattice. Both the optical lattice depth and the running lattice frequency provide tunability of the spin-motion coupling strength. The spin-motional coupling is exploited to demonstrate sideband cooling of a ^{171}Yb^{+} ion to the ground state of motion.
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Affiliation(s)
- Shiqian Ding
- Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, 117543 Singapore, Singapore
| | - Huanqian Loh
- Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, 117543 Singapore, Singapore
| | - Roland Hablutzel
- Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, 117543 Singapore, Singapore
| | - Meng Gao
- Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, 117543 Singapore, Singapore and Department of Physics, National University of Singapore, 2 Science Drive 3, 117551 Singapore, Singapore
| | - Gleb Maslennikov
- Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, 117543 Singapore, Singapore
| | - Dzmitry Matsukevich
- Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, 117543 Singapore, Singapore and Department of Physics, National University of Singapore, 2 Science Drive 3, 117551 Singapore, Singapore
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16
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Goold J, Poschinger U, Modi K. Measuring the heat exchange of a quantum process. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 90:020101. [PMID: 25215667 DOI: 10.1103/physreve.90.020101] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Indexed: 06/03/2023]
Abstract
Very recently, interferometric methods have been proposed to measure the full statistics of work performed on a driven quantum system [Dorner et al., Phys. Rev. Lett. 110, 230601 (2013) and Mazzola et al., Phys. Rev. Lett. 110, 230602 (2013)]. The advantage of such schemes is that they replace the necessity to make projective measurements by performing phase estimation on an appropriately coupled ancilla qubit. These proposals are one possible route to the tangible experimental exploration of quantum thermodynamics, a subject which is the center of much current attention due to the current control of mesoscopic quantum systems. In this Rapid Communication we demonstrate that a modification of the phase estimation protocols can be used in order to measure the heat distribution of a quantum process. In addition, we demonstrate how our scheme maybe implemented using ion trap technology. Our scheme should pave the way for experimental explorations of the Landauer principle and hence the intricate energy to information conversion in mesoscopic quantum systems.
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Affiliation(s)
- John Goold
- The Abdus Salam International Centre for Theoretical Physics (ICTP), Trieste, Italy
| | - Ulrich Poschinger
- QUANTUM, Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany
| | - Kavan Modi
- School of Physics, Monash University, Victoria 3800, Australia
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17
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Cohen I, Retzker A. Proposal for verification of the haldane phase using trapped ions. PHYSICAL REVIEW LETTERS 2014; 112:040503. [PMID: 24580427 DOI: 10.1103/physrevlett.112.040503] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Indexed: 06/03/2023]
Abstract
A proposal to use trapped ions to implement spin-one XXZ antiferromagnetic chains as an experimental tool to explore the Haldane phase is presented. We explain how to reach the Haldane phase adiabatically, demonstrate the robustness of the ground states to noise in the magnetic field and Rabi frequencies, and propose a way to detect them using their characteristics: an excitation gap and exponentially decaying correlations, a nonvanishing nonlocal string order, and a double degenerate entanglement spectrum. Scaling up to higher dimensions and more frustrated lattices, we obtain richer phase diagrams, and we can reach spin liquid phase, which can be detected by its entanglement entropy which obeys the boundary law.
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Affiliation(s)
- I Cohen
- Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem, 91904 Givat Ram, Israel
| | - A Retzker
- Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem, 91904 Givat Ram, Israel
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18
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Webster SC, Weidt S, Lake K, McLoughlin JJ, Hensinger WK. Simple manipulation of a microwave dressed-state ion qubit. PHYSICAL REVIEW LETTERS 2013; 111:140501. [PMID: 24138229 DOI: 10.1103/physrevlett.111.140501] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Indexed: 06/02/2023]
Abstract
Many schemes for implementing quantum information processing require that the atomic states used have a nonzero magnetic moment; however, such magnetically sensitive states of an atom are vulnerable to decoherence due to fluctuating magnetic fields. Dressing an atom with external fields is a powerful method of reducing such decoherence [N. Timoney et al., Nature (London) 476, 185 (2011)]. We introduce an experimentally simpler method of manipulating such a dressed-state qubit, which allows the implementation of general rotations of the qubit, and demonstrate this method using a trapped ytterbium ion.
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Affiliation(s)
- S C Webster
- Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH, United Kingdom
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19
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Navon N, Kotler S, Akerman N, Glickman Y, Almog I, Ozeri R. Addressing two-level systems variably coupled to an oscillating field. PHYSICAL REVIEW LETTERS 2013; 111:073001. [PMID: 23992060 DOI: 10.1103/physrevlett.111.073001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2012] [Indexed: 06/02/2023]
Abstract
We propose a simple method to spectrally resolve an array of identical two-level systems coupled to an inhomogeneous oscillating field. The addressing protocol uses a dressing field with a spatially dependent coupling to the atoms. We validate this scheme experimentally by realizing single-spin addressing of a linear chain of trapped ions that are separated by ~3 μm, dressed by a laser field that is resonant with the micromotion sideband of a narrow optical transition.
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Affiliation(s)
- Nir Navon
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel.
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20
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Robust site-resolvable quantum gates in an optical lattice via inhomogeneous control. Nat Commun 2013; 4:2027. [DOI: 10.1038/ncomms3027] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Accepted: 05/21/2013] [Indexed: 11/09/2022] Open
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21
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Piltz C, Scharfenberger B, Khromova A, Varón AF, Wunderlich C. Protecting conditional quantum gates by robust dynamical decoupling. PHYSICAL REVIEW LETTERS 2013; 110:200501. [PMID: 25167390 DOI: 10.1103/physrevlett.110.200501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Indexed: 06/03/2023]
Abstract
Dephasing--phase randomization of a quantum superposition state--is a major obstacle for the realization of high fidelity quantum logic operations. Here, we implement a two-qubit controlled-NOT gate using dynamical decoupling (DD), despite the gate time being more than 1 order of magnitude longer than the intrinsic coherence time of the system. For realizing this universal conditional quantum gate, we have devised a concatenated DD sequence that ensures robustness against imperfections of DD pulses that otherwise may destroy quantum information or interfere with gate dynamics. We compare its performance with three other types of DD sequences. These experiments are carried out using a well-controlled prototype quantum system--trapped atomic ions coupled by an effective spin-spin interaction. The scheme for protecting conditional quantum gates demonstrated here is applicable to other physical systems, such as nitrogen vacancy centers, solid state nuclear magnetic resonance, and circuit quantum electrodynamics.
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Affiliation(s)
- Ch Piltz
- Department Physik, Naturwissenschaftlich-Technische Fakultät, Universität Siegen, 57068 Siegen, Germany
| | - B Scharfenberger
- Department Physik, Naturwissenschaftlich-Technische Fakultät, Universität Siegen, 57068 Siegen, Germany
| | - A Khromova
- Department Physik, Naturwissenschaftlich-Technische Fakultät, Universität Siegen, 57068 Siegen, Germany
| | - A F Varón
- Department Physik, Naturwissenschaftlich-Technische Fakultät, Universität Siegen, 57068 Siegen, Germany
| | - Ch Wunderlich
- Department Physik, Naturwissenschaftlich-Technische Fakultät, Universität Siegen, 57068 Siegen, Germany
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22
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Warring U, Ospelkaus C, Colombe Y, Jördens R, Leibfried D, Wineland DJ. Individual-ion addressing with microwave field gradients. PHYSICAL REVIEW LETTERS 2013; 110:173002. [PMID: 23679718 DOI: 10.1103/physrevlett.110.173002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Indexed: 06/02/2023]
Abstract
Individual-qubit addressing is a prerequisite for many instances of quantum information processing. We demonstrate this capability on trapped-ion qubits with microwave near fields delivered by electrode structures integrated into a microfabricated surface-electrode trap. We describe four approaches that may be used in quantum information experiments with hyperfine levels as qubits. We implement individual control on two 25Mg+ ions separated by 4.3 μm and find spin-flip crosstalk errors on the order of 10(-3).
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Affiliation(s)
- U Warring
- Time and Frequency Division, National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA.
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23
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Zampetaki AV, Diakonos FK, Schmelcher P. Finite-temperature crossover from a crystalline to a cluster phase for a confined finite chain of ions. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 87:042116. [PMID: 23679382 DOI: 10.1103/physreve.87.042116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2012] [Revised: 03/29/2013] [Indexed: 06/02/2023]
Abstract
Employing Monte Carlo simulation techniques we investigate the statistical properties of equally charged particles confined in a one-dimensional box trap and detect a crossover from a crystalline to a cluster phase with increasing temperature. The corresponding transition temperature depends separately on the number of particles N and the box size L, implying nonextensivity due to the long-range character of the interactions. The probability density of the spacing between the particles exhibits at low temperatures an accumulation of discrete peaks with an overall asymmetric shape. In the vicinity of the transition temperature it is of a Gaussian form, whereas in the high-temperature regime an exponential decay is observed. The high-temperature behavior shows a cluster phase with a mean cluster size that first increases with the temperature and then saturates. The crossover is clearly identifiable also in the nonlinear behavior of the heat capacity with varying temperature. The influence of the trapping potential on the observed results as well as possible experimental realizations are briefly addressed.
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Affiliation(s)
- A V Zampetaki
- Zentrum für Optische Quantentechnologien, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
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24
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Khromova A, Piltz C, Scharfenberger B, Gloger TF, Johanning M, Varón AF, Wunderlich C. Designer spin pseudomolecule implemented with trapped ions in a magnetic gradient. PHYSICAL REVIEW LETTERS 2012; 108:220502. [PMID: 23003581 DOI: 10.1103/physrevlett.108.220502] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Indexed: 06/01/2023]
Abstract
We report on the experimental investigation of an individual pseudomolecule using trapped ions with adjustable magnetically induced J-type coupling between spin states. Resonances of individual spins are well separated and are addressed with high fidelity. Quantum gates are carried out using microwave radiation in the presence of thermal excitation of the pseudomolecule's vibrations. Demonstrating controlled-NOT gates between non-nearest neighbors serves as a proof-of-principle of a quantum bus employing a spin chain. Combining advantageous features of nuclear magnetic resonance experiments and trapped ions, respectively, opens up a new avenue toward scalable quantum information processing.
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Affiliation(s)
- A Khromova
- Department Physik, Naturwissenschaftlich-Technische Fakultät, Universität Siegen, 57068 Siegen, Germany
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25
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Schneider C, Porras D, Schaetz T. Experimental quantum simulations of many-body physics with trapped ions. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2012; 75:024401. [PMID: 22790343 DOI: 10.1088/0034-4885/75/2/024401] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Direct experimental access to some of the most intriguing quantum phenomena is not granted due to the lack of precise control of the relevant parameters in their naturally intricate environment. Their simulation on conventional computers is impossible, since quantum behaviour arising with superposition states or entanglement is not efficiently translatable into the classical language. However, one could gain deeper insight into complex quantum dynamics by experimentally simulating the quantum behaviour of interest in another quantum system, where the relevant parameters and interactions can be controlled and robust effects detected sufficiently well. Systems of trapped ions provide unique control of both the internal (electronic) and external (motional) degrees of freedom. The mutual Coulomb interaction between the ions allows for large interaction strengths at comparatively large mutual ion distances enabling individual control and readout. Systems of trapped ions therefore exhibit a prominent system in several physical disciplines, for example, quantum information processing or metrology. Here, we will give an overview of different trapping techniques of ions as well as implementations for coherent manipulation of their quantum states and discuss the related theoretical basics. We then report on the experimental and theoretical progress in simulating quantum many-body physics with trapped ions and present current approaches for scaling up to more ions and more-dimensional systems.
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Affiliation(s)
- Ch Schneider
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany
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26
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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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27
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Quantum gates and memory using microwave-dressed states. Nature 2011; 476:185-8. [DOI: 10.1038/nature10319] [Citation(s) in RCA: 179] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Accepted: 06/16/2011] [Indexed: 11/08/2022]
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28
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Förster L, Karski M, Choi JM, Steffen A, Alt W, Meschede D, Widera A, Montano E, Lee JH, Rakreungdet W, Jessen PS. Microwave control of atomic motion in optical lattices. PHYSICAL REVIEW LETTERS 2009; 103:233001. [PMID: 20366146 DOI: 10.1103/physrevlett.103.233001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Indexed: 05/29/2023]
Abstract
We control the quantum mechanical motion of neutral atoms in an optical lattice by driving microwave transitions between spin states whose trapping potentials are spatially offset. Control of this offset with nanometer precision allows for adjustment of the coupling strength between different motional states, analogous to an adjustable effective Lamb-Dicke factor. This is used both for efficient one-dimensional sideband cooling of individual atoms to a vibrational ground state population of 97% and to drive coherent Rabi oscillation between arbitrary pairs of vibrational states. We further show that microwaves can drive well resolved transitions between motional states in maximally offset, shallow lattices, and thus in principle allow for coherent control of long-range quantum transport.
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Affiliation(s)
- Leonid Förster
- Institut für Angewandte Physik, Universität Bonn, Wegelerstrasse 8, D-53115 Bonn, Germany
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