1
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Huang C, Wang C, Zhang H, Hu H, Wang Z, Mao Z, Li S, Hou P, Wu Y, Zhou Z, Duan L. Electromagnetically Induced Transparency Cooling of High-Nuclear-Spin Ions. PHYSICAL REVIEW LETTERS 2024; 133:113204. [PMID: 39331985 DOI: 10.1103/physrevlett.133.113204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Accepted: 08/26/2024] [Indexed: 09/29/2024]
Abstract
We report the electromagnetically induced transparency (EIT) cooling of ^{137}Ba^{+} ions with a nuclear spin of I=3/2, which are a good candidate of qubits for future large-scale trapped-ion quantum computing. EIT cooling of atoms or ions with a complex ground-state level structure is challenging due to the lack of an isolated Λ system, as the population can escape from the Λ system to reduce the cooling efficiency. We overcome this issue by leveraging an EIT pumping laser to repopulate the cooling subspace, ensuring continuous and effective EIT cooling. We cool the two radial modes of a single ^{137}Ba^{+} ion to average motional occupations of 0.08(5) and 0.15(7), respectively. Using the same laser parameters, we also cool all the ten radial modes of a five-ion chain to near their ground states. Our approach can be adapted to atomic species possessing similar level structures. It allows engineering of the EIT Fano-like spectrum, which can be useful for simultaneous cooling of modes across a wide frequency range, aiding in large-scale trapped-ion quantum information processing.
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Affiliation(s)
| | - Chenxi Wang
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, People's Republic of China
| | | | - Hongyuan Hu
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, People's Republic of China
| | - Zuqing Wang
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, People's Republic of China
| | - Zhichao Mao
- HYQ Co., Ltd., Beijing 100176, People's Republic of China
| | - Shijiao Li
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, People's Republic of China
| | - Panyu Hou
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, People's Republic of China
- Hefei National Laboratory, Hefei 230088, People's Republic of China
| | - Yukai Wu
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, People's Republic of China
- Hefei National Laboratory, Hefei 230088, People's Republic of China
| | - Zichao Zhou
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, People's Republic of China
- Hefei National Laboratory, Hefei 230088, People's Republic of China
| | - Luming Duan
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, People's Republic of China
- Hefei National Laboratory, Hefei 230088, People's Republic of China
- New Cornerstone Science Laboratory, Beijing 100084, People's Republic of China
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2
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O'Reilly J, Toh G, Goetting I, Saha S, Shalaev M, Carter AL, Risinger A, Kalakuntla A, Li T, Verma A, Monroe C. Fast Photon-Mediated Entanglement of Continuously Cooled Trapped Ions for Quantum Networking. PHYSICAL REVIEW LETTERS 2024; 133:090802. [PMID: 39270187 DOI: 10.1103/physrevlett.133.090802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Accepted: 07/30/2024] [Indexed: 09/15/2024]
Abstract
We entangle two cotrapped atomic barium ion qubits by collecting single visible photons from each ion through in vacuo 0.8 NA objectives, interfering them through an integrated fiber beam splitter and detecting them in coincidence. This projects the qubits into an entangled Bell state with an observed fidelity lower bound of F>94%. We also introduce an ytterbium ion for sympathetic cooling to remove the need for recooling interruptions and achieve a continuous entanglement rate of 250 s^{-1}.
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Affiliation(s)
| | - George Toh
- Duke Quantum Center, Departments of Electrical and Computer Engineering and Physics, Duke University, Durham, North Carolina 27708, USA
| | | | - Sagnik Saha
- Duke Quantum Center, Departments of Electrical and Computer Engineering and Physics, Duke University, Durham, North Carolina 27708, USA
| | - Mikhail Shalaev
- Duke Quantum Center, Departments of Electrical and Computer Engineering and Physics, Duke University, Durham, North Carolina 27708, USA
| | | | | | | | - Tingguang Li
- Duke Quantum Center, Departments of Electrical and Computer Engineering and Physics, Duke University, Durham, North Carolina 27708, USA
| | - Ashrit Verma
- Duke Quantum Center, Departments of Electrical and Computer Engineering and Physics, Duke University, Durham, North Carolina 27708, USA
| | - Christopher Monroe
- Duke Quantum Center, Departments of Electrical and Computer Engineering and Physics, Duke University, Durham, North Carolina 27708, USA
- Joint Quantum Institute, Departments of Physics and Electrical and Computer Engineering, University of Maryland, College Park, Maryland 20742, USA
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3
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Sotirova AS, Sun B, Leppard JD, Wang A, Wang M, Vazquez-Brennan A, Nadlinger DP, Moser S, Jesacher A, He C, Pokorny F, Booth MJ, Ballance CJ. Low cross-talk optical addressing of trapped-ion qubits using a novel integrated photonic chip. LIGHT, SCIENCE & APPLICATIONS 2024; 13:199. [PMID: 39164255 PMCID: PMC11335750 DOI: 10.1038/s41377-024-01542-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 07/15/2024] [Accepted: 07/17/2024] [Indexed: 08/22/2024]
Abstract
Individual optical addressing in chains of trapped atomic ions requires the generation of many small, closely spaced beams with low cross-talk. Furthermore, implementing parallel operations necessitates phase, frequency, and amplitude control of each individual beam. Here, we present a scalable method for achieving all of these capabilities using a high-performance integrated photonic chip coupled to a network of optical fibre components. The chip design results in very low cross-talk between neighbouring channels even at the micrometre-scale spacing by implementing a very high refractive index contrast between the channel core and cladding. Furthermore, the photonic chip manufacturing procedure is highly flexible, allowing for the creation of devices with an arbitrary number of channels as well as non-uniform channel spacing at the chip output. We present the system used to integrate the chip within our ion trap apparatus and characterise the performance of the full individual addressing setup using a single trapped ion as a light-field sensor. Our measurements showed intensity cross-talk below ~10-3 across the chip, with minimum observed cross-talk as low as ~10-5.
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Affiliation(s)
- Ana S Sotirova
- University of Oxford, Department of Physics, Oxford, OX1 3PU, UK.
| | - Bangshan Sun
- University of Oxford, Department of Engineering Science, Oxford, OX1 3PJ, UK.
| | - Jamie D Leppard
- University of Oxford, Department of Physics, Oxford, OX1 3PU, UK
| | - Andong Wang
- University of Oxford, Department of Engineering Science, Oxford, OX1 3PJ, UK
| | - Mohan Wang
- University of Oxford, Department of Engineering Science, Oxford, OX1 3PJ, UK
| | | | | | - Simon Moser
- Institute of Biomedical Physics, Medical University of Innsbruck, Müllerstraße 44, 6020, Innsbruck, Austria
| | - Alexander Jesacher
- Institute of Biomedical Physics, Medical University of Innsbruck, Müllerstraße 44, 6020, Innsbruck, Austria
| | - Chao He
- University of Oxford, Department of Engineering Science, Oxford, OX1 3PJ, UK
| | - Fabian Pokorny
- University of Oxford, Department of Physics, Oxford, OX1 3PU, UK
| | - Martin J Booth
- University of Oxford, Department of Engineering Science, Oxford, OX1 3PJ, UK.
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4
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Kwon J, Setzer WJ, Gehl M, Karl N, Van Der Wall J, Law R, Blain MG, Stick D, McGuinness HJ. Multi-site integrated optical addressing of trapped ions. Nat Commun 2024; 15:3709. [PMID: 38697962 PMCID: PMC11065861 DOI: 10.1038/s41467-024-47882-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 04/13/2024] [Indexed: 05/05/2024] Open
Abstract
One of the most effective ways to advance the performance of quantum computers and quantum sensors is to increase the number of qubits or quantum resources in the system. A major technical challenge that must be solved to realize this goal for trapped-ion systems is scaling the delivery of optical signals to many individual ions. In this paper we demonstrate an approach employing waveguides and multi-mode interferometer splitters to optically address multiple 171Yb+ ions in a surface trap by delivering all wavelengths required for full qubit control. Measurements of hyperfine spectra and Rabi flopping were performed on the E2 clock transition, using integrated waveguides for delivering the light needed for Doppler cooling, state preparation, coherent operations, and detection. We describe the use of splitters to address multiple ions using a single optical input per wavelength and use them to demonstrate simultaneous Rabi flopping on two different transitions occurring at distinct trap sites. This work represents an important step towards the realization of scalable integrated photonics for atomic clocks and trapped-ion quantum information systems.
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Affiliation(s)
- Joonhyuk Kwon
- Sandia National Laboratories, Albuquerque, NM, 87185, USA.
| | | | - Michael Gehl
- Sandia National Laboratories, Albuquerque, NM, 87185, USA
| | - Nicholas Karl
- Sandia National Laboratories, Albuquerque, NM, 87185, USA
| | | | - Ryan Law
- Sandia National Laboratories, Albuquerque, NM, 87185, USA
| | - Matthew G Blain
- Sandia National Laboratories, Albuquerque, NM, 87185, USA
- Quantinuum LLC, 303 S Technology Ct., Broomfield, CO, 80021, USA
| | - Daniel Stick
- Sandia National Laboratories, Albuquerque, NM, 87185, USA
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5
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Jain S, Sägesser T, Hrmo P, Torkzaban C, Stadler M, Oswald R, Axline C, Bautista-Salvador A, Ospelkaus C, Kienzler D, Home J. Penning micro-trap for quantum computing. Nature 2024; 627:510-514. [PMID: 38480890 PMCID: PMC10954548 DOI: 10.1038/s41586-024-07111-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 01/24/2024] [Indexed: 03/18/2024]
Abstract
Trapped ions in radio-frequency traps are among the leading approaches for realizing quantum computers, because of high-fidelity quantum gates and long coherence times1-3. However, the use of radio-frequencies presents several challenges to scaling, including requiring compatibility of chips with high voltages4, managing power dissipation5 and restricting transport and placement of ions6. Here we realize a micro-fabricated Penning ion trap that removes these restrictions by replacing the radio-frequency field with a 3 T magnetic field. We demonstrate full quantum control of an ion in this setting, as well as the ability to transport the ion arbitrarily in the trapping plane above the chip. This unique feature of the Penning micro-trap approach opens up a modification of the quantum charge-coupled device architecture with improved connectivity and flexibility, facilitating the realization of large-scale trapped-ion quantum computing, quantum simulation and quantum sensing.
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Affiliation(s)
- Shreyans Jain
- Department of Physics, ETH Zürich, Zurich, Switzerland.
- Quantum Center, ETH Zürich, Zurich, Switzerland.
| | - Tobias Sägesser
- Department of Physics, ETH Zürich, Zurich, Switzerland
- Quantum Center, ETH Zürich, Zurich, Switzerland
| | - Pavel Hrmo
- Department of Physics, ETH Zürich, Zurich, Switzerland
- Quantum Center, ETH Zürich, Zurich, Switzerland
| | | | - Martin Stadler
- Department of Physics, ETH Zürich, Zurich, Switzerland
- Quantum Center, ETH Zürich, Zurich, Switzerland
| | - Robin Oswald
- Department of Physics, ETH Zürich, Zurich, Switzerland
- Quantum Center, ETH Zürich, Zurich, Switzerland
| | - Chris Axline
- Department of Physics, ETH Zürich, Zurich, Switzerland
| | - Amado Bautista-Salvador
- Institut für Quantenoptik, Leibniz Universität Hannover, Hannover, Germany
- Physikalisch-Technische Bundesanstalt, Braunschweig, Germany
| | - Christian Ospelkaus
- Institut für Quantenoptik, Leibniz Universität Hannover, Hannover, Germany
- Physikalisch-Technische Bundesanstalt, Braunschweig, Germany
| | - Daniel Kienzler
- Department of Physics, ETH Zürich, Zurich, Switzerland
- Quantum Center, ETH Zürich, Zurich, Switzerland
| | - Jonathan Home
- Department of Physics, ETH Zürich, Zurich, Switzerland
- Quantum Center, ETH Zürich, Zurich, Switzerland
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6
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Carter AL, O'Reilly J, Toh G, Saha S, Shalaev M, Goetting I, Monroe C. Ion trap with in-vacuum high numerical aperture imaging for a dual-species modular quantum computer. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2024; 95:033201. [PMID: 38477652 DOI: 10.1063/5.0180732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 02/25/2024] [Indexed: 03/14/2024]
Abstract
Photonic interconnects between quantum systems will play a central role in both scalable quantum computing and quantum networking. Entanglement of remote qubits via photons has been demonstrated in many platforms; however, improving the rate of entanglement generation will be instrumental for integrating photonic links into modular quantum computers. We present an ion trap system that has the highest reported free-space photon collection efficiency for quantum networking. We use a pair of in-vacuum aspheric lenses, each with a numerical aperture of 0.8, to couple 10(1)% of the 493 nm photons emitted from a 138Ba+ ion into single-mode fibers. We also demonstrate that proximal effects of the lenses on the ion position and motion can be mitigated.
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Affiliation(s)
- Allison L Carter
- Joint Quantum Institute and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - Jameson O'Reilly
- Joint Quantum Institute and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Duke Quantum Center, Department of Electrical and Computer Engineering, Department of Physics, Duke University, Durham, North Carolina 27701, USA
| | - George Toh
- Joint Quantum Institute and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Duke Quantum Center, Department of Electrical and Computer Engineering, Department of Physics, Duke University, Durham, North Carolina 27701, USA
| | - Sagnik Saha
- Joint Quantum Institute and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Duke Quantum Center, Department of Electrical and Computer Engineering, Department of Physics, Duke University, Durham, North Carolina 27701, USA
| | - Mikhail Shalaev
- Duke Quantum Center, Department of Electrical and Computer Engineering, Department of Physics, Duke University, Durham, North Carolina 27701, USA
| | - Isabella Goetting
- Duke Quantum Center, Department of Electrical and Computer Engineering, Department of Physics, Duke University, Durham, North Carolina 27701, USA
| | - Christopher Monroe
- Joint Quantum Institute and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Duke Quantum Center, Department of Electrical and Computer Engineering, Department of Physics, Duke University, Durham, North Carolina 27701, USA
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7
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Fallek SD, Sandhu VS, McGill RA, Gray JM, Tinkey HN, Clark CR, Brown KR. Rapid exchange cooling with trapped ions. Nat Commun 2024; 15:1089. [PMID: 38316766 PMCID: PMC11258264 DOI: 10.1038/s41467-024-45232-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 01/18/2024] [Indexed: 02/07/2024] Open
Abstract
The trapped-ion quantum charge-coupled device (QCCD) architecture is a leading candidate for advanced quantum information processing. In current QCCD implementations, imperfect ion transport and anomalous heating can excite ion motion during a calculation. To counteract this, intermediate cooling is necessary to maintain high-fidelity gate performance. Cooling the computational ions sympathetically with ions of another species, a commonly employed strategy, creates a significant runtime bottleneck. Here, we demonstrate a different approach we call exchange cooling. Unlike sympathetic cooling, exchange cooling does not require trapping two different atomic species. The protocol introduces a bank of "coolant" ions which are repeatedly laser cooled. A computational ion can then be cooled by transporting a coolant ion into its proximity. We test this concept experimentally with two 40Ca+ ions, executing the necessary transport in 107 μs, an order of magnitude faster than typical sympathetic cooling durations. We remove over 96%, and as many as 102(5) quanta, of axial motional energy from the computational ion. We verify that re-cooling the coolant ion does not decohere the computational ion. This approach validates the feasibility of a single-species QCCD processor, capable of fast quantum simulation and computation.
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Affiliation(s)
| | | | - Ryan A McGill
- Georgia Tech Research Institute, Atlanta, 30332, GA, USA
| | - John M Gray
- Georgia Tech Research Institute, Atlanta, 30332, GA, USA
| | - Holly N Tinkey
- Georgia Tech Research Institute, Atlanta, 30332, GA, USA
| | - Craig R Clark
- Georgia Tech Research Institute, Atlanta, 30332, GA, USA
| | - Kenton R Brown
- Georgia Tech Research Institute, Atlanta, 30332, GA, USA
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8
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Scholl P, Shaw AL, Tsai RBS, Finkelstein R, Choi J, Endres M. Erasure conversion in a high-fidelity Rydberg quantum simulator. Nature 2023; 622:273-278. [PMID: 37821592 PMCID: PMC10567575 DOI: 10.1038/s41586-023-06516-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 08/03/2023] [Indexed: 10/13/2023]
Abstract
Minimizing and understanding errors is critical for quantum science, both in noisy intermediate scale quantum (NISQ) devices1 and for the quest towards fault-tolerant quantum computation2,3. Rydberg arrays have emerged as a prominent platform in this context4 with impressive system sizes5,6 and proposals suggesting how error-correction thresholds could be significantly improved by detecting leakage errors with single-atom resolution7,8, a form of erasure error conversion9-12. However, two-qubit entanglement fidelities in Rydberg atom arrays13,14 have lagged behind competitors15,16 and this type of erasure conversion is yet to be realized for matter-based qubits in general. Here we demonstrate both erasure conversion and high-fidelity Bell state generation using a Rydberg quantum simulator5,6,17,18. When excising data with erasure errors observed via fast imaging of alkaline-earth atoms19-22, we achieve a Bell state fidelity of [Formula: see text], which improves to [Formula: see text] when correcting for remaining state-preparation errors. We further apply erasure conversion in a quantum simulation experiment for quasi-adiabatic preparation of long-range order across a quantum phase transition, and reveal the otherwise hidden impact of these errors on the simulation outcome. Our work demonstrates the capability for Rydberg-based entanglement to reach fidelities in the 0.999 regime, with higher fidelities a question of technical improvements, and shows how erasure conversion can be utilized in NISQ devices. These techniques could be translated directly to quantum-error-correction codes with the addition of long-lived qubits7,22-24.
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Affiliation(s)
- Pascal Scholl
- California Institute of Technology, Pasadena, CA, USA
| | - Adam L Shaw
- California Institute of Technology, Pasadena, CA, USA
| | | | | | - Joonhee Choi
- California Institute of Technology, Pasadena, CA, USA
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Manuel Endres
- California Institute of Technology, Pasadena, CA, USA.
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9
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Boguslawski MJ, Wall ZJ, Vizvary SR, Moore ID, Bareian M, Allcock DTC, Wineland DJ, Hudson ER, Campbell WC. Raman Scattering Errors in Stimulated-Raman-Induced Logic Gates in ^{133}Ba^{+}. PHYSICAL REVIEW LETTERS 2023; 131:063001. [PMID: 37625070 DOI: 10.1103/physrevlett.131.063001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 07/14/2023] [Indexed: 08/27/2023]
Abstract
^{133}Ba^{+} is illuminated by a laser that is far detuned from optical transitions, and the resulting spontaneous Raman scattering rate is measured. The observed scattering rate is lower than previous theoretical estimates. The majority of the discrepancy is explained by a more accurate treatment of the scattered photon density of states. This work establishes that, contrary to previous models, there is no fundamental atomic physics limit to laser-driven quantum gates from laser-induced spontaneous Raman scattering.
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Affiliation(s)
- Matthew J Boguslawski
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, 90095 California, USA
- Challenge Institute for Quantum Computation, University of California Los Angeles, Los Angeles, 90095 California, USA
| | - Zachary J Wall
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, 90095 California, USA
| | - Samuel R Vizvary
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, 90095 California, USA
| | - Isam Daniel Moore
- Department of Physics, University of Oregon, Eugene, 97403 Oregon, USA
| | - Michael Bareian
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, 90095 California, USA
| | - David T C Allcock
- Department of Physics, University of Oregon, Eugene, 97403 Oregon, USA
| | - David J Wineland
- Department of Physics, University of Oregon, Eugene, 97403 Oregon, USA
| | - Eric R Hudson
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, 90095 California, USA
- Challenge Institute for Quantum Computation, University of California Los Angeles, Los Angeles, 90095 California, USA
- Center for Quantum Science and Engineering, University of California Los Angeles, Los Angeles, 90095 California, USA
| | - Wesley C Campbell
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, 90095 California, USA
- Challenge Institute for Quantum Computation, University of California Los Angeles, Los Angeles, 90095 California, USA
- Center for Quantum Science and Engineering, University of California Los Angeles, Los Angeles, 90095 California, USA
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10
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Srinivas R, Löschnauer CM, Malinowski M, Hughes AC, Nourshargh R, Negnevitsky V, Allcock DTC, King SA, Matthiesen C, Harty TP, Ballance CJ. Coherent Control of Trapped-Ion Qubits with Localized Electric Fields. PHYSICAL REVIEW LETTERS 2023; 131:020601. [PMID: 37505962 DOI: 10.1103/physrevlett.131.020601] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 05/23/2023] [Indexed: 07/30/2023]
Abstract
We present a new method for coherent control of trapped ion qubits in separate interaction regions of a multizone trap by simultaneously applying an electric field and a spin-dependent gradient. Both the phase and amplitude of the effective single-qubit rotation depend on the electric field, which can be localized to each zone. We demonstrate this interaction on a single ion using both laser-based and magnetic-field gradients in a surface-electrode ion trap, and measure the localization of the electric field.
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Affiliation(s)
- R Srinivas
- Oxford Ionics, Oxford, OX5 1PF, United Kingdom
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, United Kingdom
| | | | | | - A C Hughes
- Oxford Ionics, Oxford, OX5 1PF, United Kingdom
| | | | | | - D T C Allcock
- Oxford Ionics, Oxford, OX5 1PF, United Kingdom
- Department of Physics, University of Oregon, Eugene, Oregon 97403, USA
| | - S A King
- Oxford Ionics, Oxford, OX5 1PF, United Kingdom
| | | | - T P Harty
- Oxford Ionics, Oxford, OX5 1PF, United Kingdom
| | - C J Ballance
- Oxford Ionics, Oxford, OX5 1PF, United Kingdom
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, United Kingdom
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11
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Hrmo P, Wilhelm B, Gerster L, van Mourik MW, Huber M, Blatt R, Schindler P, Monz T, Ringbauer M. Native qudit entanglement in a trapped ion quantum processor. Nat Commun 2023; 14:2242. [PMID: 37076475 PMCID: PMC10115791 DOI: 10.1038/s41467-023-37375-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 03/15/2023] [Indexed: 04/21/2023] Open
Abstract
Quantum information carriers, just like most physical systems, naturally occupy high-dimensional Hilbert spaces. Instead of restricting them to a two-level subspace, these high-dimensional (qudit) quantum systems are emerging as a powerful resource for the next generation of quantum processors. Yet harnessing the potential of these systems requires efficient ways of generating the desired interaction between them. Here, we experimentally demonstrate an implementation of a native two-qudit entangling gate up to dimension 5 in a trapped-ion system. This is achieved by generalizing a recently proposed light-shift gate mechanism to generate genuine qudit entanglement in a single application of the gate. The gate seamlessly adapts to the local dimension of the system with a calibration overhead that is independent of the dimension.
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Affiliation(s)
- Pavel Hrmo
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25/4, 6020, Innsbruck, Austria.
| | - Benjamin Wilhelm
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25/4, 6020, Innsbruck, Austria
| | - Lukas Gerster
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25/4, 6020, Innsbruck, Austria
| | - Martin W van Mourik
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25/4, 6020, Innsbruck, Austria
| | - Marcus Huber
- Atominstitut, Technische Universität Wien, 1020, Vienna, Austria
- Institute for Quantum Optics and Quantum Information-IQOQI Vienna, Austrian Academy of Sciences, Boltzmanngasse 3, 1090, Vienna, Austria
| | - Rainer Blatt
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25/4, 6020, Innsbruck, Austria
- Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Technikerstraße 21a, 6020, Innsbruck, Austria
- AQT, Technikerstraße 17, 6020, Innsbruck, Austria
| | - Philipp Schindler
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25/4, 6020, Innsbruck, Austria
| | - Thomas Monz
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25/4, 6020, Innsbruck, Austria
- AQT, Technikerstraße 17, 6020, Innsbruck, Austria
| | - Martin Ringbauer
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25/4, 6020, Innsbruck, Austria
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12
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Drmota P, Main D, Nadlinger DP, Nichol BC, Weber MA, Ainley EM, Agrawal A, Srinivas R, Araneda G, Ballance CJ, Lucas DM. Robust Quantum Memory in a Trapped-Ion Quantum Network Node. PHYSICAL REVIEW LETTERS 2023; 130:090803. [PMID: 36930909 DOI: 10.1103/physrevlett.130.090803] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 01/19/2023] [Indexed: 06/18/2023]
Abstract
We integrate a long-lived memory qubit into a mixed-species trapped-ion quantum network node. Ion-photon entanglement first generated with a network qubit in ^{88}Sr^{+} is transferred to ^{43}Ca^{+} with 0.977(7) fidelity, and mapped to a robust memory qubit. We then entangle the network qubit with a second photon, without affecting the memory qubit. We perform quantum state tomography to show that the fidelity of ion-photon entanglement decays ∼70 times slower on the memory qubit. Dynamical decoupling further extends the storage duration; we measure an ion-photon entanglement fidelity of 0.81(4) after 10 s.
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Affiliation(s)
- P Drmota
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - D Main
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - D P Nadlinger
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - B C Nichol
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - M A Weber
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - E M Ainley
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - A Agrawal
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - R Srinivas
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - G Araneda
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - C J Ballance
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - D M Lucas
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
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13
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Akhtar M, Bonus F, Lebrun-Gallagher FR, Johnson NI, Siegele-Brown M, Hong S, Hile SJ, Kulmiya SA, Weidt S, Hensinger WK. A high-fidelity quantum matter-link between ion-trap microchip modules. Nat Commun 2023; 14:531. [PMID: 36754957 PMCID: PMC9908934 DOI: 10.1038/s41467-022-35285-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 11/25/2022] [Indexed: 02/10/2023] Open
Abstract
System scalability is fundamental for large-scale quantum computers (QCs) and is being pursued over a variety of hardware platforms. For QCs based on trapped ions, architectures such as the quantum charge-coupled device (QCCD) are used to scale the number of qubits on a single device. However, the number of ions that can be hosted on a single quantum computing module is limited by the size of the chip being used. Therefore, a modular approach is of critical importance and requires quantum connections between individual modules. Here, we present the demonstration of a quantum matter-link in which ion qubits are transferred between adjacent QC modules. Ion transport between adjacent modules is realised at a rate of 2424 s-1 and with an infidelity associated with ion loss during transport below 7 × 10-8. Furthermore, we show that the link does not measurably impact the phase coherence of the qubit. The quantum matter-link constitutes a practical mechanism for the interconnection of QCCD devices. Our work will facilitate the implementation of modular QCs capable of fault-tolerant utility-scale quantum computation.
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Affiliation(s)
- M. Akhtar
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK ,Universal Quantum Ltd, Brighton, BN1 6SB UK
| | - F. Bonus
- Universal Quantum Ltd, Brighton, BN1 6SB UK ,grid.83440.3b0000000121901201Department of Physics and Astronomy, University College London, London, WC1E 6BT UK
| | - F. R. Lebrun-Gallagher
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK ,Universal Quantum Ltd, Brighton, BN1 6SB UK
| | - N. I. Johnson
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK
| | - M. Siegele-Brown
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK
| | - S. Hong
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK
| | - S. J. Hile
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK
| | - S. A. Kulmiya
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK ,grid.5337.20000 0004 1936 7603Quantum Engineering Centre for Doctoral Training, University of Bristol, Bristol, BS8 1TH UK
| | - S. Weidt
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK ,Universal Quantum Ltd, Brighton, BN1 6SB UK
| | - W. K. Hensinger
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK ,Universal Quantum Ltd, Brighton, BN1 6SB UK
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14
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Shapira Y, Cohen S, Akerman N, Stern A, Ozeri R. Robust Two-Qubit Gates for Trapped Ions Using Spin-Dependent Squeezing. PHYSICAL REVIEW LETTERS 2023; 130:030602. [PMID: 36763391 DOI: 10.1103/physrevlett.130.030602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 12/07/2022] [Indexed: 06/18/2023]
Abstract
Entangling gates are an essential component of quantum computers. However, generating high-fidelity gates, in a scalable manner, remains a major challenge in all quantum information processing platforms. Accordingly, improving the fidelity and robustness of these gates has been a research focus in recent years. In trapped ions quantum computers, entangling gates are performed by driving the normal modes of motion of the ion chain, generating a spin-dependent force. Even though there has been significant progress in increasing the robustness and modularity of these gates, they are still sensitive to noise in the intensity of the driving field. Here we supplement the conventional spin-dependent displacement with spin-dependent squeezing, which creates a new interaction, that enables a gate that is robust to deviations in the amplitude of the driving field. We solve the general Hamiltonian and engineer its spectrum analytically. We also endow our gate with other, more conventional, robustness properties, making it resilient to many practical sources of noise and inaccuracies.
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Affiliation(s)
- Yotam Shapira
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Sapir Cohen
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Nitzan Akerman
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Ady Stern
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Roee Ozeri
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
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15
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Xie T, Zhao Z, Xu S, Kong X, Yang Z, Wang M, Wang Y, Shi F, Du J. 99.92%-Fidelity cnot Gates in Solids by Noise Filtering. PHYSICAL REVIEW LETTERS 2023; 130:030601. [PMID: 36763408 DOI: 10.1103/physrevlett.130.030601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 12/21/2022] [Indexed: 06/18/2023]
Abstract
Inevitable interactions with the reservoir largely degrade the performance of entangling gates, which hinders practical quantum computation from coming into existence. Here, we experimentally demonstrate a 99.920(7)%-fidelity controlled-not gate by suppressing the complicated noise in a solid-state spin system at room temperature. We found that the fidelity limited at 99% in previous works results from considering only static classical noise, and, thus, in this work, a complete noise model is constructed by also considering the time dependence and the quantum nature of the spin bath. All noises in the model are dynamically corrected by an exquisitely designed shaped pulse, giving the resulting error below 10^{-4}. The residual gate error is mainly originated from the longitudinal relaxation and the waveform distortion that can both be further reduced technically. Our noise-resistant method is universal and will benefit other solid-state spin systems.
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Affiliation(s)
- Tianyu Xie
- CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China
- CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Zhiyuan Zhao
- CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China
- CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Shaoyi Xu
- CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China
- CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Xi Kong
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China
| | - Zhiping Yang
- CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China
- CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Mengqi Wang
- CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China
- CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Ya Wang
- CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China
- CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
| | - Fazhan Shi
- CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China
- CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
- School of Biomedical Engineering and Suzhou Institute for Advanced Research, University of Science and Technology of China, Suzhou 215123, China
| | - Jiangfeng Du
- CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China
- CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
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16
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Fang C, Wang Y, Huang S, Brown KR, Kim J. Crosstalk Suppression in Individually Addressed Two-Qubit Gates in a Trapped-Ion Quantum Computer. PHYSICAL REVIEW LETTERS 2022; 129:240504. [PMID: 36563266 DOI: 10.1103/physrevlett.129.240504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 11/16/2022] [Indexed: 06/17/2023]
Abstract
Crosstalk between target and neighboring spectator qubits due to spillover of control signals represents a major error source limiting the fidelity of two-qubit entangling gates in quantum computers. We show that in our laser-driven trapped-ion system coherent crosstalk error can be modeled as residual Xσ[over ^]_{ϕ} interaction and can be actively canceled by single-qubit echoing pulses. We propose and demonstrate a crosstalk suppression scheme that eliminates all first-order crosstalk utilizing only local control of target qubits, as opposed to an existing scheme which requires control over all neighboring qubits. We report a two-qubit Bell state fidelity of 99.52(6)% with the echoing pulses applied after collective gates and 99.37(5)% with the echoing pulses applied to each gate in a five-ion chain. This scheme is widely applicable to other platforms with analogous interaction Hamiltonians.
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Affiliation(s)
- Chao Fang
- Duke Quantum Center, Duke University, Durham, North Carolina 27701, USA
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Ye Wang
- Duke Quantum Center, Duke University, Durham, North Carolina 27701, USA
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Shilin Huang
- Duke Quantum Center, Duke University, Durham, North Carolina 27701, USA
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Kenneth R Brown
- Duke Quantum Center, Duke University, Durham, North Carolina 27701, USA
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
| | - Jungsang Kim
- Duke Quantum Center, Duke University, Durham, North Carolina 27701, USA
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
- IonQ, Inc., College Park, Maryland 20740, USA
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17
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Abad T, Fernández-Pendás J, Frisk Kockum A, Johansson G. Universal Fidelity Reduction of Quantum Operations from Weak Dissipation. PHYSICAL REVIEW LETTERS 2022; 129:150504. [PMID: 36269966 DOI: 10.1103/physrevlett.129.150504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 09/19/2022] [Indexed: 06/16/2023]
Abstract
Quantum information processing is in real systems often limited by dissipation, stemming from remaining uncontrolled interaction with microscopic degrees of freedom. Given recent experimental progress, we consider weak dissipation, resulting in a small error probability per operation. Here, we find a simple formula for the fidelity reduction of any desired quantum operation, where the ideal evolution is confined to the computational subspace. Interestingly, this reduction is independent of the specific operation; it depends only on the operation time and the dissipation. Using our formula, we investigate the situation where dissipation in different parts of the system has correlations, which is detrimental for the successful application of quantum error correction. Surprisingly, we find that a large class of correlations gives the same fidelity reduction as uncorrelated dissipation of similar strength.
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Affiliation(s)
- Tahereh Abad
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Jorge Fernández-Pendás
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Anton Frisk Kockum
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Göran Johansson
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
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18
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Jia Z, Wang Y, Zhang B, Whitlow J, Fang C, Kim J, Brown KR. Determination of Multimode Motional Quantum States in a Trapped Ion System. PHYSICAL REVIEW LETTERS 2022; 129:103602. [PMID: 36112437 DOI: 10.1103/physrevlett.129.103602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 08/12/2022] [Accepted: 08/15/2022] [Indexed: 06/15/2023]
Abstract
Trapped atomic ions are a versatile platform for studying interactions between spins and bosons by coupling the internal states of the ions to their motion. Measurement of complex motional states with multiple modes is challenging, because all motional state populations can only be measured indirectly through the spin state of ions. Here we present a general method to determine the Fock state distributions and to reconstruct the density matrix of an arbitrary multimode motional state. We experimentally verify the method using different entangled states of multiple radial modes in a five-ion chain. This method can be extended to any system with Jaynes-Cummings-type interactions.
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Affiliation(s)
- Zhubing Jia
- Duke Quantum Center, Duke University, Durham, North Carolina 27701, USA
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
| | - Ye Wang
- Duke Quantum Center, Duke University, Durham, North Carolina 27701, USA
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Bichen Zhang
- Duke Quantum Center, Duke University, Durham, North Carolina 27701, USA
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Jacob Whitlow
- Duke Quantum Center, Duke University, Durham, North Carolina 27701, USA
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Chao Fang
- Duke Quantum Center, Duke University, Durham, North Carolina 27701, USA
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Jungsang Kim
- Duke Quantum Center, Duke University, Durham, North Carolina 27701, USA
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
- IonQ, Inc., College Park, Maryland 20740, USA
| | - Kenneth R Brown
- Duke Quantum Center, Duke University, Durham, North Carolina 27701, USA
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
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19
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Erickson SD, Wu JJ, Hou PY, Cole DC, Geller S, Kwiatkowski A, Glancy S, Knill E, Slichter DH, Wilson AC, Leibfried D. High-Fidelity Indirect Readout of Trapped-Ion Hyperfine Qubits. PHYSICAL REVIEW LETTERS 2022; 128:160503. [PMID: 35522486 DOI: 10.1103/physrevlett.128.160503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 03/17/2022] [Indexed: 06/14/2023]
Abstract
We propose and demonstrate a protocol for high-fidelity indirect readout of trapped ion hyperfine qubits, where the state of a ^{9}Be^{+} qubit ion is mapped to a ^{25}Mg^{+} readout ion using laser-driven Raman transitions. By partitioning the ^{9}Be^{+} ground-state hyperfine manifold into two subspaces representing the two qubit states and choosing appropriate laser parameters, the protocol can be made robust to spontaneous photon scattering errors on the Raman transitions, enabling repetition for increased readout fidelity. We demonstrate combined readout and back-action errors for the two subspaces of 1.2_{-0.6}^{+1.1}×10^{-4} and 0_{-0}^{+1.9}×10^{-5} with 68% confidence while avoiding decoherence of spectator qubits due to stray resonant light that is inherent to direct fluorescence detection.
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Affiliation(s)
- Stephen D Erickson
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Jenny J Wu
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Pan-Yu Hou
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Daniel C Cole
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - Shawn Geller
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Alex Kwiatkowski
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Scott Glancy
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - Emanuel Knill
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Center for Theory of Quantum Matter, University of Colorado, Boulder, Colorado 80309, USA
| | - Daniel H Slichter
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - Andrew C Wilson
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - Dietrich Leibfried
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
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20
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Tinkey HN, Clark CR, Sawyer BC, Brown KR. Transport-Enabled Entangling Gate for Trapped Ions. PHYSICAL REVIEW LETTERS 2022; 128:050502. [PMID: 35179924 DOI: 10.1103/physrevlett.128.050502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 01/07/2022] [Indexed: 06/14/2023]
Abstract
We implement a 2-qubit entangling Mølmer-Sørensen interaction by transporting two cotrapped ^{40}Ca^{+} ions through a stationary, bichromatic optical beam within a surface-electrode Paul trap. We describe a procedure for achieving a constant Doppler shift during the transport, which uses fine temporal adjustment of the moving confinement potential. The fixed interaction duration of the ions transported through the laser beam as well as the dynamically changing ac Stark shift require alterations to the calibration procedures used for a stationary gate. We use the interaction to produce Bell states with fidelities commensurate to those of stationary gates performed in the same system. This result establishes the feasibility of actively incorporating ion transport into quantum information entangling operations.
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Affiliation(s)
- Holly N Tinkey
- Georgia Tech Research Institute, Atlanta, Georgia 30332, USA
| | - Craig R Clark
- Georgia Tech Research Institute, Atlanta, Georgia 30332, USA
| | - Brian C Sawyer
- Georgia Tech Research Institute, Atlanta, Georgia 30332, USA
| | - Kenton R Brown
- Georgia Tech Research Institute, Atlanta, Georgia 30332, USA
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21
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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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