1
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Vaartjes A, Kringhøj A, Vine W, Day T, Morello A, Pla JJ. Strong microwave squeezing above 1 Tesla and 1 Kelvin. Nat Commun 2024; 15:4229. [PMID: 38762499 PMCID: PMC11102506 DOI: 10.1038/s41467-024-48519-3] [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: 12/20/2023] [Accepted: 05/03/2024] [Indexed: 05/20/2024] Open
Abstract
Squeezed states of light have been used extensively to increase the precision of measurements, from the detection of gravitational waves to the search for dark matter. In the optical domain, high levels of vacuum noise squeezing are possible due to the availability of low loss optical components and high-performance squeezers. At microwave frequencies, however, limitations of the squeezing devices and the high insertion loss of microwave components make squeezing vacuum noise an exceptionally difficult task. Here we demonstrate direct measurements of high levels of microwave squeezing. We use an ultra-low loss setup and weakly-nonlinear kinetic inductance parametric amplifiers to squeeze microwave noise 7.8(2) dB below the vacuum level. The amplifiers exhibit a resilience to magnetic fields and permit the demonstration of large squeezing levels inside fields of up to 2 T. Finally, we exploit the high critical temperature of our amplifiers to squeeze a warm thermal environment, achieving vacuum level noise at a temperature of 1.8 K. These results enable experiments that combine squeezing with magnetic fields and permit quantum-limited microwave measurements at elevated temperatures, significantly reducing the complexity and cost of the cryogenic systems required for such experiments.
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Affiliation(s)
- Arjen Vaartjes
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Anders Kringhøj
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Wyatt Vine
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Tom Day
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Andrea Morello
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Jarryd J Pla
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia.
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2
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Descamps É, Keller A, Milman P. Gottesman-Kitaev-Preskill Encoding in Continuous Modal Variables of Single Photons. PHYSICAL REVIEW LETTERS 2024; 132:170601. [PMID: 38728710 DOI: 10.1103/physrevlett.132.170601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 03/28/2024] [Indexed: 05/12/2024]
Abstract
GKP states, introduced by Gottesman, Kitaev, and Preskill, are continuous variable logical qubits that can be corrected for errors caused by phase space displacements. Their experimental realization is challenging, in particular, using propagating fields, where quantum information is encoded in the quadratures of the electromagnetic field. However, traveling photons are essential in many applications of GKP codes involving the long-distance transmission of quantum information. We introduce a new method for encoding GKP states in propagating fields using single photons, each occupying a distinct auxiliary mode given by the propagation direction. The GKP states are defined as highly correlated states described by collective continuous modes, as time and frequency. We analyze how the error detection and correction protocol scales with the total photon number and the spectral width. We show that the obtained code can be corrected for displacements in time-frequency phase space, which correspond to dephasing, or rotations, in the quadrature phase space and to photon losses. Most importantly, we show that generating two-photon GKP states is relatively simple, and that such states are currently produced and manipulated in several photonic platforms where frequency and time-bin biphoton entangled states can be engineered.
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Affiliation(s)
- Éloi Descamps
- Laboratoire Matériaux et Phénomènes Quantiques, Université Paris Diderot, CNRS UMR 7162, 75013 Paris, France
| | - Arne Keller
- Laboratoire Matériaux et Phénomènes Quantiques, Université Paris Diderot, CNRS UMR 7162, 75013 Paris, France
- Department de Physique, Université Paris-Saclay, 91405 Orsay Cedex, France
| | - Pérola Milman
- Laboratoire Matériaux et Phénomènes Quantiques, Université Paris Diderot, CNRS UMR 7162, 75013 Paris, France
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3
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Gutman N, Gorlach A, Tziperman O, Ruimy R, Kaminer I. Universal Control of Symmetric States Using Spin Squeezing. PHYSICAL REVIEW LETTERS 2024; 132:153601. [PMID: 38682988 DOI: 10.1103/physrevlett.132.153601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Accepted: 03/11/2024] [Indexed: 05/01/2024]
Abstract
The manipulation of quantum many-body systems is a crucial goal in quantum science. Entangled quantum states that are symmetric under qubits permutation are of growing interest. Yet, the creation and control of symmetric states has remained a challenge. Here, we introduce a method to universally control symmetric states, proposing a scheme that relies solely on coherent rotations and spin squeezing. We present protocols for the creation of different symmetric states including Schrödinger's cat and Gottesman-Kitaev-Preskill states. The obtained symmetric states can be transferred to traveling photonic states via spontaneous emission, providing a powerful approach for engineering desired quantum photonic states.
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Affiliation(s)
- Nir Gutman
- Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Alexey Gorlach
- Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Offek Tziperman
- Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Ron Ruimy
- Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Ido Kaminer
- Technion-Israel Institute of Technology, Haifa 32000, Israel
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4
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Lachance-Quirion D, Lemonde MA, Simoneau JO, St-Jean L, Lemieux P, Turcotte S, Wright W, Lacroix A, Fréchette-Viens J, Shillito R, Hopfmueller F, Tremblay M, Frattini NE, Camirand Lemyre J, St-Jean P. Autonomous Quantum Error Correction of Gottesman-Kitaev-Preskill States. PHYSICAL REVIEW LETTERS 2024; 132:150607. [PMID: 38682990 DOI: 10.1103/physrevlett.132.150607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 03/11/2024] [Indexed: 05/01/2024]
Abstract
The Gottesman-Kitaev-Preskill (GKP) code encodes a logical qubit into a bosonic system with resilience against single-photon loss, the predominant error in most bosonic systems. Here we present experimental results demonstrating quantum error correction of GKP states based on reservoir engineering of a superconducting device. Error correction is made fully autonomous through an unconditional reset of an auxiliary transmon qubit. We show that the lifetime of the logical qubit is increased from quantum error correction, therefore reaching the point at which more errors are corrected than generated.
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Affiliation(s)
| | | | | | | | | | | | - Wyatt Wright
- Nord Quantique, Sherbrooke, Québec J1J 2E2, Canada
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5
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Agrawal A, Dixit AV, Roy T, Chakram S, He K, Naik RK, Schuster DI, Chou A. Stimulated Emission of Signal Photons from Dark Matter Waves. PHYSICAL REVIEW LETTERS 2024; 132:140801. [PMID: 38640371 DOI: 10.1103/physrevlett.132.140801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 01/26/2024] [Indexed: 04/21/2024]
Abstract
The manipulation of quantum states of light has resulted in significant advancements in both dark matter searches and gravitational wave detectors. Current dark matter searches operating in the microwave frequency range use nearly quantum-limited amplifiers. Future high frequency searches will use photon counting techniques to evade the standard quantum limit. We present a signal enhancement technique that utilizes a superconducting qubit to prepare a superconducting microwave cavity in a nonclassical Fock state and stimulate the emission of a photon from a dark matter wave. By initializing the cavity in an |n=4⟩ Fock state, we demonstrate a quantum enhancement technique that increases the signal photon rate and hence also the dark matter scan rate each by a factor of 2.78. Using this technique, we conduct a dark photon search in a band around 5.965 GHz (24.67 μeV), where the kinetic mixing angle ε≥4.35×10^{-13} is excluded at the 90% confidence level.
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Affiliation(s)
- Ankur Agrawal
- James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
- Kavli Institute for Cosmological Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - Akash V Dixit
- James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
- Kavli Institute for Cosmological Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - Tanay Roy
- James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - Srivatsan Chakram
- James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Kevin He
- James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - Ravi K Naik
- Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - David I Schuster
- James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - Aaron Chou
- Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA
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6
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Kolesnikow XC, Bomantara RW, Doherty AC, Grimsmo AL. Gottesman-Kitaev-Preskill State Preparation Using Periodic Driving. PHYSICAL REVIEW LETTERS 2024; 132:130605. [PMID: 38613309 DOI: 10.1103/physrevlett.132.130605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 10/04/2023] [Accepted: 02/06/2024] [Indexed: 04/14/2024]
Abstract
The Gottesman-Kitaev-Preskill (GKP) code may be used to overcome noise in continuous variable quantum systems. However, preparing GKP states remains experimentally challenging. We propose a method for preparing GKP states by engineering a time-periodic Hamiltonian whose Floquet states are GKP states. This Hamiltonian may be realized in a superconducting circuit comprising a SQUID shunted by a superinductor and a capacitor, with a characteristic impedance twice the resistance quantum. The GKP Floquet states can be prepared by adiabatically tuning the frequency of the external magnetic flux drive. We predict that highly squeezed >11.9 dB (10.8 dB) GKP magic states can be prepared on a microsecond timescale, given a quality factor of 10^{6} (10^{5}) and flux noise at typical rates.
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Affiliation(s)
- Xanda C Kolesnikow
- Centre for Engineered Quantum Systems, School of Physics, The University of Sydney, Sydney, NSW 2006, Australia
| | - Raditya W Bomantara
- Department of Physics, Interdisciplinary Research Center for Intelligent Secure Systems, King Fahd University of Petroleum and Minerals, 31261 Dhahran, Saudi Arabia
| | - Andrew C Doherty
- Centre for Engineered Quantum Systems, School of Physics, The University of Sydney, Sydney, NSW 2006, Australia
| | - Arne L Grimsmo
- Centre for Engineered Quantum Systems, School of Physics, The University of Sydney, Sydney, NSW 2006, Australia
- AWS Center for Quantum Computing, Pasadena, California 91125, USA
- California Institute of Technology, Pasadena, California 91125, USA
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7
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Li Z, Roy T, Rodríguez Pérez D, Lee KH, Kapit E, Schuster DI. Autonomous error correction of a single logical qubit using two transmons. Nat Commun 2024; 15:1681. [PMID: 38395989 PMCID: PMC10891116 DOI: 10.1038/s41467-024-45858-z] [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: 11/14/2023] [Accepted: 02/05/2024] [Indexed: 02/25/2024] Open
Abstract
Large-scale quantum computers will inevitably need quantum error correction to protect information against decoherence. Traditional error correction typically requires many qubits, along with high-efficiency error syndrome measurement and real-time feedback. Autonomous quantum error correction instead uses steady-state bath engineering to perform the correction in a hardware-efficient manner. In this work, we develop a new autonomous quantum error correction scheme that actively corrects single-photon loss and passively suppresses low-frequency dephasing, and we demonstrate an important experimental step towards its full implementation with transmons. Compared to uncorrected encoding, improvements are experimentally witnessed for the logical zero, one, and superposition states. Our results show the potential of implementing hardware-efficient autonomous quantum error correction to enhance the reliability of a transmon-based quantum information processor.
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Affiliation(s)
- Ziqian Li
- James Franck Institute, University of Chicago, Chicago, IL, 60637, USA
- Department of Physics, University of Chicago, Chicago, IL, 60637, USA
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA
| | - Tanay Roy
- James Franck Institute, University of Chicago, Chicago, IL, 60637, USA
- Department of Physics, University of Chicago, Chicago, IL, 60637, USA
| | | | - Kan-Heng Lee
- James Franck Institute, University of Chicago, Chicago, IL, 60637, USA
- Department of Physics, University of Chicago, Chicago, IL, 60637, USA
| | - Eliot Kapit
- Department of Physics, Colorado School of Mines, Golden, CO, 80401, USA
| | - David I Schuster
- James Franck Institute, University of Chicago, Chicago, IL, 60637, USA.
- Department of Physics, University of Chicago, Chicago, IL, 60637, USA.
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA.
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL, 60637, USA.
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8
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Willsch D, Rieger D, Winkel P, Willsch M, Dickel C, Krause J, Ando Y, Lescanne R, Leghtas Z, Bronn NT, Deb P, Lanes O, Minev ZK, Dennig B, Geisert S, Günzler S, Ihssen S, Paluch P, Reisinger T, Hanna R, Bae JH, Schüffelgen P, Grützmacher D, Buimaga-Iarinca L, Morari C, Wernsdorfer W, DiVincenzo DP, Michielsen K, Catelani G, Pop IM. Observation of Josephson harmonics in tunnel junctions. NATURE PHYSICS 2024; 20:815-821. [PMID: 38799981 PMCID: PMC11116114 DOI: 10.1038/s41567-024-02400-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 01/14/2024] [Indexed: 05/29/2024]
Abstract
Approaches to developing large-scale superconducting quantum processors must cope with the numerous microscopic degrees of freedom that are ubiquitous in solid-state devices. State-of-the-art superconducting qubits employ aluminium oxide (AlOx) tunnel Josephson junctions as the sources of nonlinearity necessary to perform quantum operations. Analyses of these junctions typically assume an idealized, purely sinusoidal current-phase relation. However, this relation is expected to hold only in the limit of vanishingly low-transparency channels in the AlOx barrier. Here we show that the standard current-phase relation fails to accurately describe the energy spectra of transmon artificial atoms across various samples and laboratories. Instead, a mesoscopic model of tunnelling through an inhomogeneous AlOx barrier predicts percent-level contributions from higher Josephson harmonics. By including these in the transmon Hamiltonian, we obtain orders of magnitude better agreement between the computed and measured energy spectra. The presence and impact of Josephson harmonics has important implications for developing AlOx-based quantum technologies including quantum computers and parametric amplifiers. As an example, we show that engineered Josephson harmonics can reduce the charge dispersion and associated errors in transmon qubits by an order of magnitude while preserving their anharmonicity.
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Affiliation(s)
- Dennis Willsch
- Jülich Supercomputing Centre, Forschungszentrum Jülich, Jülich, Germany
| | - Dennis Rieger
- IQMT, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
- PHI, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Patrick Winkel
- IQMT, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
- PHI, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Departments of Applied Physics and Physics, Yale University, New Haven, CT USA
- Yale Quantum Institute, Yale University, New Haven, CT USA
| | - Madita Willsch
- Jülich Supercomputing Centre, Forschungszentrum Jülich, Jülich, Germany
- AIDAS, Jülich, Germany
| | | | - Jonas Krause
- Physics Institute II, University of Cologne, Köln, Germany
| | - Yoichi Ando
- Physics Institute II, University of Cologne, Köln, Germany
| | - Raphaël Lescanne
- LPENS, Mines Paris-PSL, ENS-PSL, Inria, Université PSL, CNRS, Paris, France
- Alice & Bob, Paris, France
| | - Zaki Leghtas
- LPENS, Mines Paris-PSL, ENS-PSL, Inria, Université PSL, CNRS, Paris, France
| | - Nicholas T. Bronn
- IBM Quantum, IBM T. J. Watson Research Center, Yorktown Heights, NY USA
| | - Pratiti Deb
- IBM Quantum, IBM T. J. Watson Research Center, Yorktown Heights, NY USA
| | - Olivia Lanes
- IBM Quantum, IBM T. J. Watson Research Center, Yorktown Heights, NY USA
| | - Zlatko K. Minev
- IBM Quantum, IBM T. J. Watson Research Center, Yorktown Heights, NY USA
| | - Benedikt Dennig
- IQMT, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
- PHI, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Simon Geisert
- IQMT, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - Simon Günzler
- IQMT, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - Sören Ihssen
- IQMT, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - Patrick Paluch
- IQMT, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
- PHI, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Thomas Reisinger
- IQMT, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - Roudy Hanna
- PGI-9, Forschungszentrum Jülich and JARA Jülich-Aachen Research Alliance, Jülich, Germany
- RWTH Aachen University, Aachen, Germany
| | - Jin Hee Bae
- PGI-9, Forschungszentrum Jülich and JARA Jülich-Aachen Research Alliance, Jülich, Germany
| | - Peter Schüffelgen
- PGI-9, Forschungszentrum Jülich and JARA Jülich-Aachen Research Alliance, Jülich, Germany
| | - Detlev Grützmacher
- PGI-9, Forschungszentrum Jülich and JARA Jülich-Aachen Research Alliance, Jülich, Germany
- RWTH Aachen University, Aachen, Germany
| | | | | | - Wolfgang Wernsdorfer
- IQMT, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
- PHI, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - David P. DiVincenzo
- RWTH Aachen University, Aachen, Germany
- PGI-2, Forschungszentrum Jülich, Jülich, Germany
| | - Kristel Michielsen
- Jülich Supercomputing Centre, Forschungszentrum Jülich, Jülich, Germany
- AIDAS, Jülich, Germany
- RWTH Aachen University, Aachen, Germany
| | - Gianluigi Catelani
- PGI-11, Forschungszentrum Jülich, Jülich, Germany
- Quantum Research Center, Technology Innovation Institute, Abu Dhabi, UAE
| | - Ioan M. Pop
- IQMT, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
- PHI, Karlsruhe Institute of Technology, Karlsruhe, Germany
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9
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Grebel J, Yan H, Chou MH, Andersson G, Conner CR, Joshi YJ, Miller JM, Povey RG, Qiao H, Wu X, Cleland AN. Bidirectional Multiphoton Communication between Remote Superconducting Nodes. PHYSICAL REVIEW LETTERS 2024; 132:047001. [PMID: 38335327 DOI: 10.1103/physrevlett.132.047001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 12/11/2023] [Indexed: 02/12/2024]
Abstract
Quantum communication test beds provide a useful resource for experimentally investigating a variety of communication protocols. Here we demonstrate a superconducting circuit test bed with bidirectional multiphoton state transfer capability using time-domain shaped wave packets. The system we use to achieve this comprises two remote nodes, each including a tunable superconducting transmon qubit and a tunable microwave-frequency resonator, linked by a 2 m-long superconducting coplanar waveguide, which serves as a transmission line. We transfer both individual and superposition Fock states between the two remote nodes, and additionally show that this bidirectional state transfer can be done simultaneously, as well as being used to entangle elements in the two nodes.
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Affiliation(s)
- Joel Grebel
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
| | - Haoxiong Yan
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
| | - Ming-Han Chou
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - Gustav Andersson
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
| | - Christopher R Conner
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
| | - Yash J Joshi
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
| | - Jacob M Miller
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - Rhys G Povey
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - Hong Qiao
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
| | - Xuntao Wu
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
| | - Andrew N Cleland
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
- Center for Molecular Engineering, Argonne National Laboratory, Lemont, Illinois 60439, USA
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10
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Geier M, Krøjer S, von Oppen F, Marcus CM, Flensberg K, Brouwer PW. Non-Abelian Holonomy of Majorana Zero Modes Coupled to a Chaotic Quantum Dot. PHYSICAL REVIEW LETTERS 2024; 132:036604. [PMID: 38307057 DOI: 10.1103/physrevlett.132.036604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 10/24/2023] [Accepted: 12/16/2023] [Indexed: 02/04/2024]
Abstract
If a quantum dot is coupled to a topological superconductor via tunneling contacts, each contact hosts a Majorana zero mode in the limit of zero transmission. Close to a resonance and at a finite contact transparency, the resonant level in the quantum dot couples the Majorana modes, but a ground-state degeneracy per fermion parity subspace remains if the number of Majorana modes coupled to the dot is five or larger. Upon varying shape-defining gate voltages while remaining close to resonance, a nontrivial evolution within the degenerate ground-state manifold is achieved. We characterize the corresponding non-Abelian holonomy for a quantum dot with chaotic classical dynamics using random matrix theory and discuss measurable signatures of the non-Abelian time evolution.
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Affiliation(s)
- Max Geier
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Svend Krøjer
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Felix von Oppen
- Dahlem Center for Complex Quantum Systems and Physics Department, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Charles M Marcus
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Karsten Flensberg
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Piet W Brouwer
- Dahlem Center for Complex Quantum Systems and Physics Department, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
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11
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Guo L, Peano V. Engineering Arbitrary Hamiltonians in Phase Space. PHYSICAL REVIEW LETTERS 2024; 132:023602. [PMID: 38277589 DOI: 10.1103/physrevlett.132.023602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 06/27/2023] [Accepted: 11/27/2023] [Indexed: 01/28/2024]
Abstract
We introduce a general method to engineer arbitrary Hamiltonians in the Floquet phase space of a periodically driven oscillator, based on the noncommutative Fourier transformation technique. We establish the relationship between an arbitrary target Floquet Hamiltonian in phase space and the periodic driving potential in real space. We obtain analytical expressions for the driving potentials in real space that can generate novel Hamiltonians in phase space, e.g., rotational lattices and sharp-boundary wells. Our protocol can be realized in a range of experimental platforms for nonclassical state generation and bosonic quantum computation.
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Affiliation(s)
- Lingzhen Guo
- Center for Joint Quantum Studies and Department of Physics, School of Science, Tianjin University, Tianjin 300072, China
- Max Planck Institute for the Science of Light, Staudtstrasse 2, 91058 Erlangen, Germany
| | - Vittorio Peano
- Max Planck Institute for the Science of Light, Staudtstrasse 2, 91058 Erlangen, Germany
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12
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Hanamura F, Asavanant W, Kikura S, Mishima M, Miki S, Terai H, Yabuno M, China F, Fukui K, Endo M, Furusawa A. Single-Shot Single-Mode Optical Two-Parameter Displacement Estimation beyond Classical Limit. PHYSICAL REVIEW LETTERS 2023; 131:230801. [PMID: 38134775 DOI: 10.1103/physrevlett.131.230801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 10/31/2023] [Indexed: 12/24/2023]
Abstract
Uncertainty principle prohibits the precise measurement of both components of displacement parameters in phase space. We have theoretically shown that this limit can be beaten using single-photon states, in a single-shot and single-mode setting [F. Hanamura et al., Estimation of gaussian random displacement using non-gaussian states, Phys. Rev. A 104, 062601 (2021).PLRAAN2469-992610.1103/PhysRevA.104.062601]. In this Letter, we validate this by experimentally beating the classical limit. In optics, this is the first experiment to estimate both parameters of displacement using non-Gaussian states. This result is related to many important applications, such as quantum error correction.
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Affiliation(s)
- Fumiya Hanamura
- Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Warit Asavanant
- Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
- Optical Quantum Computing Research Team, RIKEN Center for Quantum Computing, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Seigo Kikura
- Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Moeto Mishima
- Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Shigehito Miki
- Advanced ICT Research Institute, National Institute of Information and Communications Technology, 588-2 Iwaoka, Nishi-ku, Kobe, Hyogo 651-2492, Japan
- Graduate School of Engineering, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-0013, Japan
| | - Hirotaka Terai
- Advanced ICT Research Institute, National Institute of Information and Communications Technology, 588-2 Iwaoka, Nishi-ku, Kobe, Hyogo 651-2492, Japan
| | - Masahiro Yabuno
- Advanced ICT Research Institute, National Institute of Information and Communications Technology, 588-2 Iwaoka, Nishi-ku, Kobe, Hyogo 651-2492, Japan
| | - Fumihiro China
- Advanced ICT Research Institute, National Institute of Information and Communications Technology, 588-2 Iwaoka, Nishi-ku, Kobe, Hyogo 651-2492, Japan
| | - Kosuke Fukui
- Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Mamoru Endo
- Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
- Optical Quantum Computing Research Team, RIKEN Center for Quantum Computing, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Akira Furusawa
- Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
- Optical Quantum Computing Research Team, RIKEN Center for Quantum Computing, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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13
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Fukui K, Matsuura T, Menicucci NC. Efficient Concatenated Bosonic Code for Additive Gaussian Noise. PHYSICAL REVIEW LETTERS 2023; 131:170603. [PMID: 37955490 DOI: 10.1103/physrevlett.131.170603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 06/23/2023] [Accepted: 08/21/2023] [Indexed: 11/14/2023]
Abstract
Bosonic codes offer noise resilience for quantum information processing. Good performance often comes at a price of complex decoding schemes, limiting their practicality. Here, we propose using a Gottesman-Kitaev-Preskill code to detect and discard error-prone qubits, concatenated with a quantum parity code to handle the residual errors. Our method employs a simple linear-time decoder that nevertheless offers significant performance improvements over the standard decoder. Our Letter may have applications in a wide range of quantum computation and communication scenarios.
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Affiliation(s)
- Kosuke Fukui
- Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Takaya Matsuura
- Centre for Quantum Computation and Communication Technology, School of Science, RMIT University, Melbourne, Victoria 3000, Australia
| | - Nicolas C Menicucci
- Centre for Quantum Computation and Communication Technology, School of Science, RMIT University, Melbourne, Victoria 3000, Australia
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14
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He XL, Lu Y, Bao DQ, Xue H, Jiang WB, Wang Z, Roudsari AF, Delsing P, Tsai JS, Lin ZR. Fast generation of Schrödinger cat states using a Kerr-tunable superconducting resonator. Nat Commun 2023; 14:6358. [PMID: 37821443 PMCID: PMC10567735 DOI: 10.1038/s41467-023-42057-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 09/28/2023] [Indexed: 10/13/2023] Open
Abstract
Schrödinger cat states, quantum superpositions of macroscopically distinct classical states, are an important resource for quantum communication, quantum metrology and quantum computation. Especially, cat states in a phase space protected against phase-flip errors can be used as a logical qubit. However, cat states, normally generated in three-dimensional cavities and/or strong multi-photon drives, are facing the challenges of scalability and controllability. Here, we present a strategy to generate and preserve cat states in a coplanar superconducting circuit by the fast modulation of Kerr nonlinearity. At the Kerr-free work point, our cat states are passively preserved due to the vanishing Kerr effect. We are able to prepare a 2-component cat state in our chip-based device with a fidelity reaching 89.1% under a 96 ns gate time. Our scheme shows an excellent route to constructing a chip-based bosonic quantum processor.
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Affiliation(s)
- X L He
- National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050, Shanghai, China
- University of Chinese Academy of Science, 100049, Beijing, China
| | - Yong Lu
- 3rd Physikalisches Institut, University of Stuttgart, 70569, Stuttgart, Germany.
- Microtechnology and Nanoscience, Chalmers University of Technology, SE-412 96, Göteborg, Sweden.
| | - D Q Bao
- National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050, Shanghai, China
- University of Chinese Academy of Science, 100049, Beijing, China
| | - Hang Xue
- National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050, Shanghai, China
- University of Chinese Academy of Science, 100049, Beijing, China
| | - W B Jiang
- National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050, Shanghai, China
- University of Chinese Academy of Science, 100049, Beijing, China
| | - Z Wang
- National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050, Shanghai, China
- University of Chinese Academy of Science, 100049, Beijing, China
| | - A F Roudsari
- Microtechnology and Nanoscience, Chalmers University of Technology, SE-412 96, Göteborg, Sweden
| | - Per Delsing
- Microtechnology and Nanoscience, Chalmers University of Technology, SE-412 96, Göteborg, Sweden
| | - J S Tsai
- Graduate School of Science, Tokyo University of Science, Shinjuku, Tokyo, 162-0825, Japan
- Center for Quantum Computing, RIKEN, Wako, Saitama, 351-0198, Japan
| | - Z R Lin
- National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050, Shanghai, China.
- University of Chinese Academy of Science, 100049, Beijing, China.
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15
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Teoh JD, Winkel P, Babla HK, Chapman BJ, Claes J, de Graaf SJ, Garmon JWO, Kalfus WD, Lu Y, Maiti A, Sahay K, Thakur N, Tsunoda T, Xue SH, Frunzio L, Girvin SM, Puri S, Schoelkopf RJ. Dual-rail encoding with superconducting cavities. Proc Natl Acad Sci U S A 2023; 120:e2221736120. [PMID: 37801473 PMCID: PMC10576063 DOI: 10.1073/pnas.2221736120] [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: 12/22/2022] [Accepted: 08/07/2023] [Indexed: 10/08/2023] Open
Abstract
The design of quantum hardware that reduces and mitigates errors is essential for practical quantum error correction (QEC) and useful quantum computation. To this end, we introduce the circuit-Quantum Electrodynamics (QED) dual-rail qubit in which our physical qubit is encoded in the single-photon subspace, [Formula: see text], of two superconducting microwave cavities. The dominant photon loss errors can be detected and converted into erasure errors, which are in general much easier to correct. In contrast to linear optics, a circuit-QED implementation of the dual-rail code offers unique capabilities. Using just one additional transmon ancilla per dual-rail qubit, we describe how to perform a gate-based set of universal operations that includes state preparation, logical readout, and parametrizable single and two-qubit gates. Moreover, first-order hardware errors in the cavities and the transmon can be detected and converted to erasure errors in all operations, leaving background Pauli errors that are orders of magnitude smaller. Hence, the dual-rail cavity qubit exhibits a favorable hierarchy of error rates and is expected to perform well below the relevant QEC thresholds with today's coherence times.
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Affiliation(s)
- James D. Teoh
- Department of Applied Physics, Yale University, New Haven, CT06511
- Department of Physics, Yale University, New Haven, CT06511
- Yale Quantum Institute, Yale University, New Haven, CT06511
| | - Patrick Winkel
- Department of Applied Physics, Yale University, New Haven, CT06511
- Department of Physics, Yale University, New Haven, CT06511
- Yale Quantum Institute, Yale University, New Haven, CT06511
| | - Harshvardhan K. Babla
- Department of Applied Physics, Yale University, New Haven, CT06511
- Department of Physics, Yale University, New Haven, CT06511
- Yale Quantum Institute, Yale University, New Haven, CT06511
| | - Benjamin J. Chapman
- Department of Applied Physics, Yale University, New Haven, CT06511
- Department of Physics, Yale University, New Haven, CT06511
- Yale Quantum Institute, Yale University, New Haven, CT06511
| | - Jahan Claes
- Department of Applied Physics, Yale University, New Haven, CT06511
- Department of Physics, Yale University, New Haven, CT06511
- Yale Quantum Institute, Yale University, New Haven, CT06511
| | - Stijn J. de Graaf
- Department of Applied Physics, Yale University, New Haven, CT06511
- Department of Physics, Yale University, New Haven, CT06511
- Yale Quantum Institute, Yale University, New Haven, CT06511
| | - John W. O. Garmon
- Department of Applied Physics, Yale University, New Haven, CT06511
- Department of Physics, Yale University, New Haven, CT06511
- Yale Quantum Institute, Yale University, New Haven, CT06511
| | - William D. Kalfus
- Department of Applied Physics, Yale University, New Haven, CT06511
- Department of Physics, Yale University, New Haven, CT06511
- Yale Quantum Institute, Yale University, New Haven, CT06511
| | - Yao Lu
- Department of Applied Physics, Yale University, New Haven, CT06511
- Department of Physics, Yale University, New Haven, CT06511
- Yale Quantum Institute, Yale University, New Haven, CT06511
| | - Aniket Maiti
- Department of Applied Physics, Yale University, New Haven, CT06511
- Department of Physics, Yale University, New Haven, CT06511
- Yale Quantum Institute, Yale University, New Haven, CT06511
| | - Kaavya Sahay
- Department of Applied Physics, Yale University, New Haven, CT06511
- Department of Physics, Yale University, New Haven, CT06511
- Yale Quantum Institute, Yale University, New Haven, CT06511
| | - Neel Thakur
- Department of Applied Physics, Yale University, New Haven, CT06511
- Department of Physics, Yale University, New Haven, CT06511
- Yale Quantum Institute, Yale University, New Haven, CT06511
| | - Takahiro Tsunoda
- Department of Applied Physics, Yale University, New Haven, CT06511
- Department of Physics, Yale University, New Haven, CT06511
- Yale Quantum Institute, Yale University, New Haven, CT06511
| | - Sophia H. Xue
- Department of Applied Physics, Yale University, New Haven, CT06511
- Department of Physics, Yale University, New Haven, CT06511
- Yale Quantum Institute, Yale University, New Haven, CT06511
| | - Luigi Frunzio
- Department of Applied Physics, Yale University, New Haven, CT06511
- Department of Physics, Yale University, New Haven, CT06511
- Yale Quantum Institute, Yale University, New Haven, CT06511
| | - Steven M. Girvin
- Department of Applied Physics, Yale University, New Haven, CT06511
- Department of Physics, Yale University, New Haven, CT06511
- Yale Quantum Institute, Yale University, New Haven, CT06511
| | - Shruti Puri
- Department of Applied Physics, Yale University, New Haven, CT06511
- Department of Physics, Yale University, New Haven, CT06511
- Yale Quantum Institute, Yale University, New Haven, CT06511
| | - Robert J. Schoelkopf
- Department of Applied Physics, Yale University, New Haven, CT06511
- Department of Physics, Yale University, New Haven, CT06511
- Yale Quantum Institute, Yale University, New Haven, CT06511
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16
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Somoroff A, Ficheux Q, Mencia RA, Xiong H, Kuzmin R, Manucharyan VE. Millisecond Coherence in a Superconducting Qubit. PHYSICAL REVIEW LETTERS 2023; 130:267001. [PMID: 37450803 DOI: 10.1103/physrevlett.130.267001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 03/24/2023] [Accepted: 05/10/2023] [Indexed: 07/18/2023]
Abstract
Improving control over physical qubits is a crucial component of quantum computing research. Here we report a superconducting fluxonium qubit with uncorrected coherence time T_{2}^{*}=1.48±0.13 ms, exceeding the state of the art for transmons by an order of magnitude. The average gate fidelity was benchmarked at 0.99991(1). Notably, even in the millisecond range, the coherence time is limited by material absorption and could be further improved with a more rigorous fabrication. Our demonstration may be useful for suppressing errors in the next generation quantum processors.
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Affiliation(s)
- Aaron Somoroff
- Department of Physics, Joint Quantum Institute, and Quantum Materials Center, University of Maryland, College Park, Maryland 20742, USA
| | - Quentin Ficheux
- Department of Physics, Joint Quantum Institute, and Quantum Materials Center, University of Maryland, College Park, Maryland 20742, USA
| | - Raymond A Mencia
- Department of Physics, Joint Quantum Institute, and Quantum Materials Center, University of Maryland, College Park, Maryland 20742, USA
| | - Haonan Xiong
- Department of Physics, Joint Quantum Institute, and Quantum Materials Center, University of Maryland, College Park, Maryland 20742, USA
| | - Roman Kuzmin
- Department of Physics, Joint Quantum Institute, and Quantum Materials Center, University of Maryland, College Park, Maryland 20742, USA
| | - Vladimir E Manucharyan
- Department of Physics, Joint Quantum Institute, and Quantum Materials Center, University of Maryland, College Park, Maryland 20742, USA
- École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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17
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Ahmed S, Quijandría F, Kockum AF. Gradient-Descent Quantum Process Tomography by Learning Kraus Operators. PHYSICAL REVIEW LETTERS 2023; 130:150402. [PMID: 37115870 DOI: 10.1103/physrevlett.130.150402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 02/17/2023] [Accepted: 03/16/2023] [Indexed: 06/19/2023]
Abstract
We perform quantum process tomography (QPT) for both discrete- and continuous-variable quantum systems by learning a process representation using Kraus operators. The Kraus form ensures that the reconstructed process is completely positive. To make the process trace preserving, we use a constrained gradient-descent (GD) approach on the so-called Stiefel manifold during optimization to obtain the Kraus operators. Our ansatz uses a few Kraus operators to avoid direct estimation of large process matrices, e.g., the Choi matrix, for low-rank quantum processes. The GD-QPT matches the performance of both compressed-sensing (CS) and projected least-squares (PLS) QPT in benchmarks with two-qubit random processes, but shines by combining the best features of these two methods. Similar to CS (but unlike PLS), GD-QPT can reconstruct a process from just a small number of random measurements, and similar to PLS (but unlike CS) it also works for larger system sizes, up to at least five qubits. We envisage that the data-driven approach of GD-QPT can become a practical tool that greatly reduces the cost and computational effort for QPT in intermediate-scale quantum systems.
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Affiliation(s)
- Shahnawaz Ahmed
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Fernando Quijandría
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
- Quantum Machines Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
| | - Anton Frisk Kockum
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
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18
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Ni Z, Li S, Deng X, Cai Y, Zhang L, Wang W, Yang ZB, Yu H, Yan F, Liu S, Zou CL, Sun L, Zheng SB, Xu Y, Yu D. Beating the break-even point with a discrete-variable-encoded logical qubit. Nature 2023; 616:56-60. [PMID: 36949191 PMCID: PMC10076216 DOI: 10.1038/s41586-023-05784-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 02/02/2023] [Indexed: 03/24/2023]
Abstract
Quantum error correction (QEC) aims to protect logical qubits from noises by using the redundancy of a large Hilbert space, which allows errors to be detected and corrected in real time1. In most QEC codes2-8, a logical qubit is encoded in some discrete variables, for example photon numbers, so that the encoded quantum information can be unambiguously extracted after processing. Over the past decade, repetitive QEC has been demonstrated with various discrete-variable-encoded scenarios9-17. However, extending the lifetimes of thus-encoded logical qubits beyond the best available physical qubit still remains elusive, which represents a break-even point for judging the practical usefulness of QEC. Here we demonstrate a QEC procedure in a circuit quantum electrodynamics architecture18, where the logical qubit is binomially encoded in photon-number states of a microwave cavity8, dispersively coupled to an auxiliary superconducting qubit. By applying a pulse featuring a tailored frequency comb to the auxiliary qubit, we can repetitively extract the error syndrome with high fidelity and perform error correction with feedback control accordingly, thereby exceeding the break-even point by about 16% lifetime enhancement. Our work illustrates the potential of hardware-efficient discrete-variable encodings for fault-tolerant quantum computation19.
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Affiliation(s)
- Zhongchu Ni
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China
- Department of Physics, Southern University of Science and Technology, Shenzhen, China
| | - Sai Li
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Xiaowei Deng
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Yanyan Cai
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Libo Zhang
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Weiting Wang
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, China
| | - Zhen-Biao Yang
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, China
| | - Haifeng Yu
- Beijing Academy of Quantum Information Sciences, Beijing, China
| | - Fei Yan
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Song Liu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China
- International Quantum Academy, and Shenzhen Branch, Hefei National Laboratory, Shenzhen, China
| | - Chang-Ling Zou
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, China
- Hefei National Laboratory, Hefei, China
| | - Luyan Sun
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, China.
- Hefei National Laboratory, Hefei, China.
| | - Shi-Biao Zheng
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, China.
| | - Yuan Xu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China.
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China.
- International Quantum Academy, and Shenzhen Branch, Hefei National Laboratory, Shenzhen, China.
| | - Dapeng Yu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China.
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China.
- Department of Physics, Southern University of Science and Technology, Shenzhen, China.
- International Quantum Academy, and Shenzhen Branch, Hefei National Laboratory, Shenzhen, China.
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19
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Sivak VV, Eickbusch A, Royer B, Singh S, Tsioutsios I, Ganjam S, Miano A, Brock BL, Ding AZ, Frunzio L, Girvin SM, Schoelkopf RJ, Devoret MH. Real-time quantum error correction beyond break-even. Nature 2023; 616:50-55. [PMID: 36949196 DOI: 10.1038/s41586-023-05782-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 02/02/2023] [Indexed: 03/24/2023]
Abstract
The ambition of harnessing the quantum for computation is at odds with the fundamental phenomenon of decoherence. The purpose of quantum error correction (QEC) is to counteract the natural tendency of a complex system to decohere. This cooperative process, which requires participation of multiple quantum and classical components, creates a special type of dissipation that removes the entropy caused by the errors faster than the rate at which these errors corrupt the stored quantum information. Previous experimental attempts to engineer such a process1-7 faced the generation of an excessive number of errors that overwhelmed the error-correcting capability of the process itself. Whether it is practically possible to utilize QEC for extending quantum coherence thus remains an open question. Here we answer it by demonstrating a fully stabilized and error-corrected logical qubit whose quantum coherence is substantially longer than that of all the imperfect quantum components involved in the QEC process, beating the best of them with a coherence gain of G = 2.27 ± 0.07. We achieve this performance by combining innovations in several domains including the fabrication of superconducting quantum circuits and model-free reinforcement learning.
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Affiliation(s)
- V V Sivak
- Department of Physics, Yale University, New Haven, CT, USA.
- Department of Applied Physics, Yale University, New Haven, CT, USA.
- Yale Quantum Institute, Yale University, New Haven, CT, USA.
- Google AI Quantum, Santa Barbara, CA, USA.
| | - A Eickbusch
- Department of Physics, Yale University, New Haven, CT, USA
- Department of Applied Physics, Yale University, New Haven, CT, USA
- Yale Quantum Institute, Yale University, New Haven, CT, USA
| | - B Royer
- Department of Physics, Yale University, New Haven, CT, USA
- Department of Applied Physics, Yale University, New Haven, CT, USA
- Yale Quantum Institute, Yale University, New Haven, CT, USA
- Institut Quantique, Université de Sherbrooke, Sherbrooke, Quebec, Canada
- Département de Physique, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - S Singh
- Department of Physics, Yale University, New Haven, CT, USA
- Department of Applied Physics, Yale University, New Haven, CT, USA
- Yale Quantum Institute, Yale University, New Haven, CT, USA
| | - I Tsioutsios
- Department of Physics, Yale University, New Haven, CT, USA
- Department of Applied Physics, Yale University, New Haven, CT, USA
- Yale Quantum Institute, Yale University, New Haven, CT, USA
| | - S Ganjam
- Department of Physics, Yale University, New Haven, CT, USA
- Department of Applied Physics, Yale University, New Haven, CT, USA
- Yale Quantum Institute, Yale University, New Haven, CT, USA
| | - A Miano
- Department of Physics, Yale University, New Haven, CT, USA
- Department of Applied Physics, Yale University, New Haven, CT, USA
- Yale Quantum Institute, Yale University, New Haven, CT, USA
| | - B L Brock
- Department of Physics, Yale University, New Haven, CT, USA
- Department of Applied Physics, Yale University, New Haven, CT, USA
- Yale Quantum Institute, Yale University, New Haven, CT, USA
| | - A Z Ding
- Department of Physics, Yale University, New Haven, CT, USA
- Department of Applied Physics, Yale University, New Haven, CT, USA
- Yale Quantum Institute, Yale University, New Haven, CT, USA
| | - L Frunzio
- Department of Physics, Yale University, New Haven, CT, USA
- Department of Applied Physics, Yale University, New Haven, CT, USA
- Yale Quantum Institute, Yale University, New Haven, CT, USA
| | - S M Girvin
- Department of Physics, Yale University, New Haven, CT, USA
- Department of Applied Physics, Yale University, New Haven, CT, USA
- Yale Quantum Institute, Yale University, New Haven, CT, USA
| | - R J Schoelkopf
- Department of Physics, Yale University, New Haven, CT, USA
- Department of Applied Physics, Yale University, New Haven, CT, USA
- Yale Quantum Institute, Yale University, New Haven, CT, USA
| | - M H Devoret
- Department of Physics, Yale University, New Haven, CT, USA.
- Department of Applied Physics, Yale University, New Haven, CT, USA.
- Yale Quantum Institute, Yale University, New Haven, CT, USA.
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20
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Zhang Y, Niu D, Shabani A, Shapourian H. Quantum Volume for Photonic Quantum Processors. PHYSICAL REVIEW LETTERS 2023; 130:110602. [PMID: 37001084 DOI: 10.1103/physrevlett.130.110602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 02/28/2023] [Indexed: 06/19/2023]
Abstract
Defining metrics for near-term quantum computing processors has been an integral part of the quantum hardware research and development efforts. Such quantitative characteristics are not only useful for reporting the progress and comparing different quantum platforms but also essential for identifying the bottlenecks and designing a technology road map. Most metrics such as randomized benchmarking and quantum volume were originally introduced for circuit-based quantum computers and were not immediately applicable to measurement-based quantum computing (MBQC) processors such as in photonic devices. In this Letter, we close this long-standing gap by presenting a framework to map physical noises and imperfections in MBQC processes to logical errors in equivalent quantum circuits, whereby enabling the well-known metrics to characterize MBQC. To showcase our framework, we study a continuous-variable cluster state based on the Gottesman-Kitaev-Preskill (GKP) encoding as a near-term candidate for photonic quantum computing, and derive the effective logical gate error channels and calculate the quantum volume in terms of the GKP squeezing and photon transmission rate.
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Affiliation(s)
- Yuxuan Zhang
- Cisco Quantum Lab, San Jose, California 95134, USA
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Daoheng Niu
- Cisco Quantum Lab, San Jose, California 95134, USA
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
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21
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Xiang ZL, Olivares DG, García-Ripoll JJ, Rabl P. Universal Time-Dependent Control Scheme for Realizing Arbitrary Linear Bosonic Transformations. PHYSICAL REVIEW LETTERS 2023; 130:050801. [PMID: 36800447 DOI: 10.1103/physrevlett.130.050801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 01/13/2023] [Indexed: 06/18/2023]
Abstract
We study the implementation of arbitrary excitation-conserving linear transformations between two sets of N stationary bosonic modes, which are connected through a photonic quantum channel. By controlling the individual couplings between the modes and the channel, an initial N-partite quantum state in register A can be released as a multiphoton wave packet and, successively, be reabsorbed in register B. Here we prove that there exists a set of control pulses that implement this transfer with arbitrarily high fidelity and, simultaneously, realize a prespecified N×N unitary transformation between the two sets of modes. Moreover, we provide a numerical algorithm for constructing these control pulses and discuss the scaling and robustness of this protocol in terms of several illustrative examples. By being purely control-based and not relying on any adaptations of the underlying hardware, the presented scheme is extremely flexible and can find widespread applications, for example, for boson-sampling experiments, multiqubit state transfer protocols, or in continuous-variable quantum computing architectures.
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Affiliation(s)
- Ze-Liang Xiang
- School of Physics, Sun Yat-sen University, Guangzhou 510275, China
| | | | | | - Peter Rabl
- Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, Stadionallee 2, 1020 Vienna, Austria
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22
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Suppressing quantum errors by scaling a surface code logical qubit. Nature 2023; 614:676-681. [PMID: 36813892 PMCID: PMC9946823 DOI: 10.1038/s41586-022-05434-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 10/10/2022] [Indexed: 02/24/2023]
Abstract
Practical quantum computing will require error rates well below those achievable with physical qubits. Quantum error correction1,2 offers a path to algorithmically relevant error rates by encoding logical qubits within many physical qubits, for which increasing the number of physical qubits enhances protection against physical errors. However, introducing more qubits also increases the number of error sources, so the density of errors must be sufficiently low for logical performance to improve with increasing code size. Here we report the measurement of logical qubit performance scaling across several code sizes, and demonstrate that our system of superconducting qubits has sufficient performance to overcome the additional errors from increasing qubit number. We find that our distance-5 surface code logical qubit modestly outperforms an ensemble of distance-3 logical qubits on average, in terms of both logical error probability over 25 cycles and logical error per cycle ((2.914 ± 0.016)% compared to (3.028 ± 0.023)%). To investigate damaging, low-probability error sources, we run a distance-25 repetition code and observe a 1.7 × 10-6 logical error per cycle floor set by a single high-energy event (1.6 × 10-7 excluding this event). We accurately model our experiment, extracting error budgets that highlight the biggest challenges for future systems. These results mark an experimental demonstration in which quantum error correction begins to improve performance with increasing qubit number, illuminating the path to reaching the logical error rates required for computation.
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23
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High-fidelity qutrit entangling gates for superconducting circuits. Nat Commun 2022; 13:7481. [PMID: 36470858 PMCID: PMC9722686 DOI: 10.1038/s41467-022-34851-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 11/08/2022] [Indexed: 12/12/2022] Open
Abstract
Ternary quantum information processing in superconducting devices poses a promising alternative to its more popular binary counterpart through larger, more connected computational spaces and proposed advantages in quantum simulation and error correction. Although generally operated as qubits, transmons have readily addressable higher levels, making them natural candidates for operation as quantum three-level systems (qutrits). Recent works in transmon devices have realized high fidelity single qutrit operation. Nonetheless, effectively engineering a high-fidelity two-qutrit entanglement remains a central challenge for realizing qutrit processing in a transmon device. In this work, we apply the differential AC Stark shift to implement a flexible, microwave-activated, and dynamic cross-Kerr entanglement between two fixed-frequency transmon qutrits, expanding on work performed for the ZZ interaction with transmon qubits. We then use this interaction to engineer efficient, high-fidelity qutrit CZ† and CZ gates, with estimated process fidelities of 97.3(1)% and 95.2(3)% respectively, a significant step forward for operating qutrits on a multi-transmon device.
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24
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Unimon qubit. Nat Commun 2022; 13:6895. [DOI: 10.1038/s41467-022-34614-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 10/28/2022] [Indexed: 11/13/2022] Open
Abstract
AbstractSuperconducting qubits seem promising for useful quantum computers, but the currently wide-spread qubit designs and techniques do not yet provide high enough performance. Here, we introduce a superconducting-qubit type, the unimon, which combines the desired properties of increased anharmonicity, full insensitivity to dc charge noise, reduced sensitivity to flux noise, and a simple structure consisting only of a single Josephson junction in a resonator. In agreement with our quantum models, we measure the qubit frequency, ω01/(2π), and increased anharmonicity α/(2π) at the optimal operation point, yielding, for example, 99.9% and 99.8% fidelity for 13 ns single-qubit gates on two qubits with (ω01, α) = (4.49 GHz, 434 MHz) × 2π and (3.55 GHz, 744 MHz) × 2π, respectively. The energy relaxation seems to be dominated by dielectric losses. Thus, improvements of the design, materials, and gate time may promote the unimon to break the 99.99% fidelity target for efficient quantum error correction and possible useful quantum advantage with noisy systems.
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25
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Liu R, V. Romero S, Oregi I, Osaba E, Villar-Rodriguez E, Ban Y. Digital Quantum Simulation and Circuit Learning for the Generation of Coherent States. ENTROPY (BASEL, SWITZERLAND) 2022; 24:1529. [PMID: 36359621 PMCID: PMC9689327 DOI: 10.3390/e24111529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/20/2022] [Accepted: 10/21/2022] [Indexed: 06/16/2023]
Abstract
Coherent states, known as displaced vacuum states, play an important role in quantum information processing, quantum machine learning, and quantum optics. In this article, two ways to digitally prepare coherent states in quantum circuits are introduced. First, we construct the displacement operator by decomposing it into Pauli matrices via ladder operators, i.e., creation and annihilation operators. The high fidelity of the digitally generated coherent states is verified compared with the Poissonian distribution in Fock space. Secondly, by using Variational Quantum Algorithms, we choose different ansatzes to generate coherent states. The quantum resources-such as numbers of quantum gates, layers and iterations-are analyzed for quantum circuit learning. The simulation results show that quantum circuit learning can provide high fidelity on learning coherent states by choosing appropriate ansatzes.
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Affiliation(s)
- Ruilin Liu
- School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China
| | - Sebastián V. Romero
- TECNALIA, Basque Research and Technology Alliance (BRTA), 48160 Derio, Spain
| | - Izaskun Oregi
- TECNALIA, Basque Research and Technology Alliance (BRTA), 48160 Derio, Spain
- Faculty of New Interactive Technologies, Universidad EUNEIZ, 01013 Vitoria-Gasteiz, Spain
| | - Eneko Osaba
- TECNALIA, Basque Research and Technology Alliance (BRTA), 48160 Derio, Spain
| | | | - Yue Ban
- TECNALIA, Basque Research and Technology Alliance (BRTA), 48160 Derio, Spain
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26
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Frunzio L, Singh S. Error-Correcting Surface Codes Get Experimental Vetting. PHYSICS 2022. [DOI: 10.1103/physics.15.103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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27
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Podhora L, Lachman L, Pham T, Lešundák A, Číp O, Slodička L, Filip R. Quantum Non-Gaussianity of Multiphonon States of a Single Atom. PHYSICAL REVIEW LETTERS 2022; 129:013602. [PMID: 35841581 DOI: 10.1103/physrevlett.129.013602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 03/22/2022] [Accepted: 05/25/2022] [Indexed: 06/15/2023]
Abstract
Quantum non-Gaussian mechanical states are already required in a range of applications. The discrete building blocks of such states are the energy eigenstates-Fock states. Despite progress in their preparation, the remaining imperfections can still invisibly cause loss of the aspects critical for their applications. We derive and apply the most challenging hierarchy of quantum non-Gaussian criteria on the characterization of single trapped-ion oscillator mechanical Fock states with up to 10 phonons. We analyze the depth of these quantum non-Gaussian features under intrinsic mechanical heating and predict their requirement for reaching quantum advantage in the sensing of a mechanical force.
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Affiliation(s)
- L Podhora
- Department of Optics, Palacký University, 17. listopadu 12, 77146 Olomouc, Czech Republic
| | - L Lachman
- Department of Optics, Palacký University, 17. listopadu 12, 77146 Olomouc, Czech Republic
| | - T Pham
- Institute of Scientific Instruments of the Czech Academy of Sciences, Královopolská 147, 612 64 Brno, Czech Republic
| | - A Lešundák
- Institute of Scientific Instruments of the Czech Academy of Sciences, Královopolská 147, 612 64 Brno, Czech Republic
| | - O Číp
- Institute of Scientific Instruments of the Czech Academy of Sciences, Královopolská 147, 612 64 Brno, Czech Republic
| | - L Slodička
- Department of Optics, Palacký University, 17. listopadu 12, 77146 Olomouc, Czech Republic
| | - R Filip
- Department of Optics, Palacký University, 17. listopadu 12, 77146 Olomouc, Czech Republic
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28
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Fukui K, Takeda S, Endo M, Asavanant W, Yoshikawa JI, van Loock P, Furusawa A. Efficient Backcasting Search for Optical Quantum State Synthesis. PHYSICAL REVIEW LETTERS 2022; 128:240503. [PMID: 35776478 DOI: 10.1103/physrevlett.128.240503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 05/19/2022] [Indexed: 06/15/2023]
Abstract
Non-Gaussian states are essential for many optical quantum technologies. The so-called optical quantum state synthesizer (OQSS), consisting of Gaussian input states, linear optics, and photon-number resolving detectors, is a promising method for non-Gaussian state preparation. However, an inevitable and crucial problem is the complexity of the numerical simulation of the state preparation on a classical computer. This problem makes it very challenging to generate important non-Gaussian states required for advanced quantum information processing. Thus, an efficient method to design OQSS circuits is highly desirable. To circumvent the problem, we offer a scheme employing a backcasting approach, where the circuit of OQSS is divided into some sublayers, and we simulate the OQSS backwards from final to first layers. Moreover, our results show that the detected photon number by each detector is at most 2, which can significantly reduce the requirements for the photon-number resolving detector. By virtue of the potential for the preparation of a wide variety of non-Gaussian states, the proposed OQSS can be a key ingredient in general optical quantum information processing.
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Affiliation(s)
- Kosuke Fukui
- Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Shuntaro Takeda
- Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Mamoru Endo
- Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Warit Asavanant
- Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Jun-Ichi Yoshikawa
- Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Peter van Loock
- Institute of Physics, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany
| | - Akira Furusawa
- Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
- Optical Quantum Computing Research Team, RIKEN Center for Quantum Computing, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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29
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Delaney RD, Urmey MD, Mittal S, Brubaker BM, Kindem JM, Burns PS, Regal CA, Lehnert KW. Superconducting-qubit readout via low-backaction electro-optic transduction. Nature 2022; 606:489-493. [PMID: 35705821 DOI: 10.1038/s41586-022-04720-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 04/04/2022] [Indexed: 11/09/2022]
Abstract
Entangling microwave-frequency superconducting quantum processors through optical light at ambient temperature would enable means of secure communication and distributed quantum information processing1. However, transducing quantum signals between these disparate regimes of the electro-magnetic spectrum remains an outstanding goal2-9, and interfacing superconducting qubits, which are constrained to operate at millikelvin temperatures, with electro-optic transducers presents considerable challenges owing to the deleterious effects of optical photons on superconductors9,10. Moreover, many remote entanglement protocols11-14 require multiple qubit gates both preceding and following the upconversion of the quantum state, and thus an ideal transducer should impart minimal backaction15 on the qubit. Here we demonstrate readout of a superconducting transmon qubit through a low-backaction electro-optomechanical transducer. The modular nature of the transducer and circuit quantum electrodynamics system used in this work enable complete isolation of the qubit from optical photons, and the backaction on the qubit from the transducer is less than that imparted by thermal radiation from the environment. Moderate improvements in the transducer bandwidth and the added noise will enable us to leverage the full suite of tools available in circuit quantum electrodynamics to demonstrate transduction of non-classical signals from a superconducting qubit to the optical domain.
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Affiliation(s)
- R D Delaney
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, CO, USA. .,Department of Physics, University of Colorado, Boulder, CO, USA.
| | - M D Urmey
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, CO, USA.,Department of Physics, University of Colorado, Boulder, CO, USA
| | - S Mittal
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, CO, USA.,Department of Physics, University of Colorado, Boulder, CO, USA
| | - B M Brubaker
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, CO, USA.,Department of Physics, University of Colorado, Boulder, CO, USA
| | - J M Kindem
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, CO, USA.,Department of Physics, University of Colorado, Boulder, CO, USA
| | - P S Burns
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, CO, USA.,Department of Physics, University of Colorado, Boulder, CO, USA
| | - C A Regal
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, CO, USA.,Department of Physics, University of Colorado, Boulder, CO, USA
| | - K W Lehnert
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, CO, USA.,Department of Physics, University of Colorado, Boulder, CO, USA.,National Institute of Standards and Technology, Boulder, CO, USA
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30
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Krinner S, Lacroix N, Remm A, Di Paolo A, Genois E, Leroux C, Hellings C, Lazar S, Swiadek F, Herrmann J, Norris GJ, Andersen CK, Müller M, Blais A, Eichler C, Wallraff A. Realizing repeated quantum error correction in a distance-three surface code. Nature 2022; 605:669-674. [PMID: 35614249 DOI: 10.1038/s41586-022-04566-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 02/09/2022] [Indexed: 11/09/2022]
Abstract
Quantum computers hold the promise of solving computational problems that are intractable using conventional methods1. For fault-tolerant operation, quantum computers must correct errors occurring owing to unavoidable decoherence and limited control accuracy2. Here we demonstrate quantum error correction using the surface code, which is known for its exceptionally high tolerance to errors3-6. Using 17 physical qubits in a superconducting circuit, we encode quantum information in a distance-three logical qubit, building on recent distance-two error-detection experiments7-9. In an error-correction cycle taking only 1.1 μs, we demonstrate the preservation of four cardinal states of the logical qubit. Repeatedly executing the cycle, we measure and decode both bit-flip and phase-flip error syndromes using a minimum-weight perfect-matching algorithm in an error-model-free approach and apply corrections in post-processing. We find a low logical error probability of 3% per cycle when rejecting experimental runs in which leakage is detected. The measured characteristics of our device agree well with a numerical model. Our demonstration of repeated, fast and high-performance quantum error-correction cycles, together with recent advances in ion traps10, support our understanding that fault-tolerant quantum computation will be practically realizable.
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Affiliation(s)
| | | | - Ants Remm
- Department of Physics, ETH Zurich, Zurich, Switzerland
| | - Agustin Di Paolo
- Institut Quantique, Université de Sherbrooke, Sherbrooke, Québec, Canada.,Département de Physique, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Elie Genois
- Institut Quantique, Université de Sherbrooke, Sherbrooke, Québec, Canada.,Département de Physique, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Catherine Leroux
- Institut Quantique, Université de Sherbrooke, Sherbrooke, Québec, Canada.,Département de Physique, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | | | | | | | | | | | - Christian Kraglund Andersen
- Department of Physics, ETH Zurich, Zurich, Switzerland.,QuTech and Kavli Institute for Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Markus Müller
- Institute for Quantum Information, RWTH Aachen University, Aachen, Germany.,Peter Grünberg Institute, Theoretical Nanoelectronics, Forschungszentrum Jülich, Jülich, Germany
| | - Alexandre Blais
- Institut Quantique, Université de Sherbrooke, Sherbrooke, Québec, Canada.,Département de Physique, Université de Sherbrooke, Sherbrooke, Québec, Canada.,Canadian Institute for Advanced Research, Toronto, Ontario, Canada
| | | | - Andreas Wallraff
- Department of Physics, ETH Zurich, Zurich, Switzerland.,Quantum Center, ETH Zurich, Zurich, Switzerland
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31
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Abobeih MH, Wang Y, Randall J, Loenen SJH, Bradley CE, Markham M, Twitchen DJ, Terhal BM, Taminiau TH. Fault-tolerant operation of a logical qubit in a diamond quantum processor. Nature 2022; 606:884-889. [PMID: 35512730 PMCID: PMC9242857 DOI: 10.1038/s41586-022-04819-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 04/28/2022] [Indexed: 11/24/2022]
Abstract
Solid-state spin qubits is a promising platform for quantum computation and quantum networks1,2. Recent experiments have demonstrated high-quality control over multi-qubit systems3–8, elementary quantum algorithms8–11 and non-fault-tolerant error correction12–14. Large-scale systems will require using error-corrected logical qubits that are operated fault tolerantly, so that reliable computation becomes possible despite noisy operations15–18. Overcoming imperfections in this way remains an important outstanding challenge for quantum science15,19–27. Here, we demonstrate fault-tolerant operations on a logical qubit using spin qubits in diamond. Our approach is based on the five-qubit code with a recently discovered flag protocol that enables fault tolerance using a total of seven qubits28–30. We encode the logical qubit using a new protocol based on repeated multi-qubit measurements and show that it outperforms non-fault-tolerant encoding schemes. We then fault-tolerantly manipulate the logical qubit through a complete set of single-qubit Clifford gates. Finally, we demonstrate flagged stabilizer measurements with real-time processing of the outcomes. Such measurements are a primitive for fault-tolerant quantum error correction. Although future improvements in fidelity and the number of qubits will be required to suppress logical error rates below the physical error rates, our realization of fault-tolerant protocols on the logical-qubit level is a key step towards quantum information processing based on solid-state spins. By using a five-qubit error-correcting code with a recently discovered flag protocol, a logical qubit that is operated fault-tolerantly is realized based on solid-state spin qubits in diamond.
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Affiliation(s)
- M H Abobeih
- QuTech, Delft University of Technology, Delft, The Netherlands.,Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, The Netherlands
| | - Y Wang
- QuTech, Delft University of Technology, Delft, The Netherlands
| | - J Randall
- QuTech, Delft University of Technology, Delft, The Netherlands.,Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, The Netherlands
| | - S J H Loenen
- QuTech, Delft University of Technology, Delft, The Netherlands.,Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, The Netherlands
| | - C E Bradley
- QuTech, Delft University of Technology, Delft, The Netherlands.,Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, The Netherlands
| | | | | | - B M Terhal
- QuTech, Delft University of Technology, Delft, The Netherlands.,JARA Institute for Quantum Information, Forschungszentrum Juelich, Juelich, Germany
| | - T H Taminiau
- QuTech, Delft University of Technology, Delft, The Netherlands. .,Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, The Netherlands.
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32
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Hastrup J, Andersen UL. Protocol for Generating Optical Gottesman-Kitaev-Preskill States with Cavity QED. PHYSICAL REVIEW LETTERS 2022; 128:170503. [PMID: 35570420 DOI: 10.1103/physrevlett.128.170503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 02/22/2022] [Indexed: 06/15/2023]
Abstract
Gottesman-Kitaev-Preskill (GKP) states are a central resource for fault-tolerant optical continuous-variable quantum computing. However, their realization in the optical domain remains to be demonstrated. Here we propose a method for preparing GKP states using a cavity QED system that can be realized in several platforms, such as trapped atoms, quantum dots, or diamond color centers. We then further combine the protocol with the previously proposed breeding protocol by Vasconcelos et al. to relax the demands on the quality of the QED system, finding that GKP states with more than 10 dB squeezing could be achieved in near-future experiments.
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Affiliation(s)
- Jacob Hastrup
- Center for Macroscopic Quantum States (bigQ), Department of Physics, Technical University of Denmark, Building 307, Fysikvej, 2800 Kongens Lyngby, Denmark
| | - Ulrik L Andersen
- Center for Macroscopic Quantum States (bigQ), Department of Physics, Technical University of Denmark, Building 307, Fysikvej, 2800 Kongens Lyngby, Denmark
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33
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Rojkov I, Layden D, Cappellaro P, Home J, Reiter F. Bias in Error-Corrected Quantum Sensing. PHYSICAL REVIEW LETTERS 2022; 128:140503. [PMID: 35476469 DOI: 10.1103/physrevlett.128.140503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 12/21/2021] [Accepted: 01/28/2022] [Indexed: 06/14/2023]
Abstract
The sensitivity afforded by quantum sensors is limited by decoherence. Quantum error correction (QEC) can enhance sensitivity by suppressing decoherence, but it has a side effect: it biases a sensor's output in realistic settings. If unaccounted for, this bias can systematically reduce a sensor's performance in experiment, and also give misleading values for the minimum detectable signal in theory. We analyze this effect in the experimentally motivated setting of continuous-time QEC, showing both how one can remedy it, and how incorrect results can arise when one does not.
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Affiliation(s)
- Ivan Rojkov
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - David Layden
- Research Laboratory of Electronics and Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Paola Cappellaro
- Research Laboratory of Electronics and Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Jonathan Home
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - Florentin Reiter
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
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34
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Hastrup J, Park K, Brask JB, Filip R, Andersen UL. Universal Unitary Transfer of Continuous-Variable Quantum States into a Few Qubits. PHYSICAL REVIEW LETTERS 2022; 128:110503. [PMID: 35363012 DOI: 10.1103/physrevlett.128.110503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 02/14/2022] [Indexed: 06/14/2023]
Abstract
We present a protocol for transferring arbitrary continuous-variable quantum states into a few discrete-variable qubits and back. The protocol is deterministic and utilizes only two-mode Rabi-type interactions that are readily available in trapped-ion and superconducting circuit platforms. The inevitable errors caused by transferring an infinite-dimensional state into a finite-dimensional register are suppressed exponentially with the number of qubits. Furthermore, the encoded states exhibit robustness against noise, such as dephasing and amplitude damping, acting on the qubits. Our protocol thus provides a powerful and flexible tool for discrete-continuous hybrid quantum systems.
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Affiliation(s)
- Jacob Hastrup
- Center for Macroscopic Quantum States (bigQ), Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Kimin Park
- Center for Macroscopic Quantum States (bigQ), Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
- Department of Optics, Palacky Univeristy, 77146 Olomouc, Czech Republic
| | - Jonatan Bohr Brask
- Center for Macroscopic Quantum States (bigQ), Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Radim Filip
- Department of Optics, Palacky Univeristy, 77146 Olomouc, Czech Republic
| | - Ulrik Lund Andersen
- Center for Macroscopic Quantum States (bigQ), Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
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35
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Gong M, Yuan X, Wang S, Wu Y, Zhao Y, Zha C, Li S, Zhang Z, Zhao Q, Liu Y, Liang F, Lin J, Xu Y, Deng H, Rong H, Lu H, Benjamin SC, Peng CZ, Ma X, Chen YA, Zhu X, Pan JW. Experimental exploration of five-qubit quantum error-correcting code with superconducting qubits. Natl Sci Rev 2022; 9:nwab011. [PMID: 35070323 PMCID: PMC8776549 DOI: 10.1093/nsr/nwab011] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 12/25/2020] [Accepted: 12/25/2020] [Indexed: 11/22/2022] Open
Abstract
Quantum error correction is an essential ingredient for universal quantum computing. Despite tremendous experimental efforts in the study of quantum error correction, to date, there has been no demonstration in the realisation of universal quantum error-correcting code, with the subsequent verification of all key features including the identification of an arbitrary physical error, the capability for transversal manipulation of the logical state and state decoding. To address this challenge, we experimentally realise the [5, 1, 3] code, the so-called smallest perfect code that permits corrections of generic single-qubit errors. In the experiment, having optimised the encoding circuit, we employ an array of superconducting qubits to realise the [5, 1, 3] code for several typical logical states including the magic state, an indispensable resource for realising non-Clifford gates. The encoded states are prepared with an average fidelity of \documentclass[12pt]{minimal}
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}{}$57.1(3)\%$\end{document} while with a high fidelity of \documentclass[12pt]{minimal}
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}{}$98.6(1)\%$\end{document} in the code space. Then, the arbitrary single-qubit errors introduced manually are identified by measuring the stabilisers. We further implement logical Pauli operations with a fidelity of \documentclass[12pt]{minimal}
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}{}$97.2(2)\%$\end{document} within the code space. Finally, we realise the decoding circuit and recover the input state with an overall fidelity of \documentclass[12pt]{minimal}
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}{}$74.5(6)\%$\end{document}, in total with 92 gates. Our work demonstrates each key aspect of the [5, 1, 3] code and verifies the viability of experimental realisation of quantum error-correcting codes with superconducting qubits.
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Affiliation(s)
- Ming Gong
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Xiao Yuan
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Shiyu Wang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yulin Wu
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Youwei Zhao
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Chen Zha
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Shaowei Li
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Zhen Zhang
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
| | - Qi Zhao
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
| | - Yunchao Liu
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
| | - Futian Liang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Jin Lin
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yu Xu
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Hui Deng
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Hao Rong
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - He Lu
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Simon C Benjamin
- Department of Materials, University of Oxford, Oxford OX1 3PH, UK
| | - Cheng-Zhi Peng
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Xiongfeng Ma
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
| | - Yu-Ao Chen
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Xiaobo Zhu
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Jian-Wei Pan
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
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36
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Lingenfelter A, Roberts D, Clerk AA. Unconditional Fock state generation using arbitrarily weak photonic nonlinearities. SCIENCE ADVANCES 2021; 7:eabj1916. [PMID: 34826241 PMCID: PMC8626069 DOI: 10.1126/sciadv.abj1916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 10/06/2021] [Indexed: 06/13/2023]
Abstract
We present a mechanism that harnesses extremely weak Kerr-type nonlinearities in a single driven cavity to deterministically generate single-photon Fock states and more general photon-blockaded states. Our method is effective even for nonlinearities that are orders-of-magnitude smaller than photonic loss. It is also completely distinct from so-called unconventional photon blockade mechanisms, as the generated states are non-Gaussian, exhibit a sharp cutoff in their photon number distribution, and can be arbitrarily close to a single-photon Fock state. Our ideas require only standard linear and parametric drives and are hence compatible with a variety of different photonic platforms.
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Affiliation(s)
- Andrew Lingenfelter
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
- Department of Physics, University of Chicago, Chicago, IL 60637, USA
| | - David Roberts
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
- Department of Physics, University of Chicago, Chicago, IL 60637, USA
| | - A. A. Clerk
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
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37
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Zens M, Krimer DO, Dhar HS, Rotter S. Periodic Cavity State Revivals from Atomic Frequency Combs. PHYSICAL REVIEW LETTERS 2021; 127:180402. [PMID: 34767418 DOI: 10.1103/physrevlett.127.180402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 10/04/2021] [Indexed: 06/13/2023]
Abstract
Spin ensembles with a comb-shaped spectrum have shown exciting properties as efficient quantum memories. Here, we present a rigorous theoretical study of such atomic frequency combs in the strong coupling limit of cavity QED, based on a full quantum treatment using tensor-network methods. Our results demonstrate that arbitrary multiphoton states in the cavity are almost perfectly absorbed by the spin ensemble and reemitted as parity-flipped states at periodic time intervals. Fidelity values near unity are achieved in these revived states by compensating for energy shifts induced by the strong spin-cavity coupling through adjustments of individual coupling values of the teeth in the atomic frequency comb.
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Affiliation(s)
- Matthias Zens
- Institute for Theoretical Physics, Vienna University of Technology (TU Wien), Wiedner Hauptstraße 8-10/136, A-1040 Vienna, Austria
| | - Dmitry O Krimer
- Institute for Theoretical Physics, Vienna University of Technology (TU Wien), Wiedner Hauptstraße 8-10/136, A-1040 Vienna, Austria
| | - Himadri S Dhar
- Department of Physics, Indian Institute of Technology, Bombay, Powai, Mumbai 400076, India
| | - Stefan Rotter
- Institute for Theoretical Physics, Vienna University of Technology (TU Wien), Wiedner Hauptstraße 8-10/136, A-1040 Vienna, Austria
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38
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Egan L, Debroy DM, Noel C, Risinger A, Zhu D, Biswas D, Newman M, Li M, Brown KR, Cetina M, Monroe C. Fault-tolerant control of an error-corrected qubit. Nature 2021; 598:281-286. [PMID: 34608286 DOI: 10.1038/s41586-021-03928-y] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 08/18/2021] [Indexed: 02/08/2023]
Abstract
Quantum error correction protects fragile quantum information by encoding it into a larger quantum system1,2. These extra degrees of freedom enable the detection and correction of errors, but also increase the control complexity of the encoded logical qubit. Fault-tolerant circuits contain the spread of errors while controlling the logical qubit, and are essential for realizing error suppression in practice3-6. Although fault-tolerant design works in principle, it has not previously been demonstrated in an error-corrected physical system with native noise characteristics. Here we experimentally demonstrate fault-tolerant circuits for the preparation, measurement, rotation and stabilizer measurement of a Bacon-Shor logical qubit using 13 trapped ion qubits. When we compare these fault-tolerant protocols to non-fault-tolerant protocols, we see significant reductions in the error rates of the logical primitives in the presence of noise. The result of fault-tolerant design is an average state preparation and measurement error of 0.6 per cent and a Clifford gate error of 0.3 per cent after offline error correction. In addition, we prepare magic states with fidelities that exceed the distillation threshold7, demonstrating all of the key single-qubit ingredients required for universal fault-tolerant control. These results demonstrate that fault-tolerant circuits enable highly accurate logical primitives in current quantum systems. With improved two-qubit gates and the use of intermediate measurements, a stabilized logical qubit can be achieved.
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Affiliation(s)
- Laird Egan
- Joint Quantum Institute, Center for Quantum Information and Computer Science, University of Maryland, College Park, MD, USA. .,Department of Physics, University of Maryland, College Park, MD, USA. .,IonQ, Inc, College Park, MD, USA.
| | - Dripto M Debroy
- Department of Physics, Duke University, Durham, NC, USA.,Google Research, Venice, CA, USA
| | - Crystal Noel
- Joint Quantum Institute, Center for Quantum Information and Computer Science, University of Maryland, College Park, MD, USA.,Department of Physics, University of Maryland, College Park, MD, USA
| | - Andrew Risinger
- Joint Quantum Institute, Center for Quantum Information and Computer Science, University of Maryland, College Park, MD, USA.,Department of Physics, University of Maryland, College Park, MD, USA.,Department of Electrical and Computer Engineering, University of Maryland, College Park, MD, USA
| | - Daiwei Zhu
- Joint Quantum Institute, Center for Quantum Information and Computer Science, University of Maryland, College Park, MD, USA.,Department of Physics, University of Maryland, College Park, MD, USA.,Department of Electrical and Computer Engineering, University of Maryland, College Park, MD, USA
| | - Debopriyo Biswas
- Joint Quantum Institute, Center for Quantum Information and Computer Science, University of Maryland, College Park, MD, USA.,Department of Physics, University of Maryland, College Park, MD, USA
| | - Michael Newman
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA.,Google Research, Venice, CA, USA
| | - Muyuan Li
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA.,School of Computational Science and Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Kenneth R Brown
- Department of Physics, Duke University, Durham, NC, USA.,Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA.,School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA.,School of Computational Science and Engineering, Georgia Institute of Technology, Atlanta, GA, USA.,Department of Chemistry, Duke University, Durham, NC, USA
| | - Marko Cetina
- Joint Quantum Institute, Center for Quantum Information and Computer Science, University of Maryland, College Park, MD, USA.,Department of Physics, University of Maryland, College Park, MD, USA
| | - Christopher Monroe
- Joint Quantum Institute, Center for Quantum Information and Computer Science, University of Maryland, College Park, MD, USA.,Department of Physics, University of Maryland, College Park, MD, USA.,Department of Electrical and Computer Engineering, University of Maryland, College Park, MD, USA.,Department of Physics, Duke University, Durham, NC, USA.,Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA.,IonQ, Inc, College Park, MD, USA
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39
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Ma WL, Puri S, Schoelkopf RJ, Devoret MH, Girvin SM, Jiang L. Quantum control of bosonic modes with superconducting circuits. Sci Bull (Beijing) 2021; 66:1789-1805. [PMID: 36654386 DOI: 10.1016/j.scib.2021.05.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 05/20/2021] [Accepted: 05/24/2021] [Indexed: 01/20/2023]
Abstract
Bosonic modes have wide applications in various quantum technologies, such as optical photons for quantum communication, magnons in spin ensembles for quantum information storage and mechanical modes for reversible microwave-to-optical quantum transduction. There is emerging interest in utilizing bosonic modes for quantum information processing, with circuit quantum electrodynamics (circuit QED) as one of the leading architectures. Quantum information can be encoded into subspaces of a bosonic superconducting cavity mode with long coherence time. However, standard Gaussian operations (e.g., beam splitting and two-mode squeezing) are insufficient for universal quantum computing. The major challenge is to introduce additional nonlinear control beyond Gaussian operations without adding significant bosonic loss or decoherence. Here we review recent advances in universal control of a single bosonic code with superconducting circuits, including unitary control, quantum feedback control, driven-dissipative control and holonomic dissipative control. Various approaches to entangling different bosonic modes are also discussed.
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Affiliation(s)
- Wen-Long Ma
- State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China; Pritzker School of Molecular Engineering, University of Chicago, Illinois 60637, USA
| | - Shruti Puri
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06511, USA; Yale Quantum Institute, Yale University, New Haven, Connecticut 06511, USA
| | - Robert J Schoelkopf
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06511, USA; Yale Quantum Institute, Yale University, New Haven, Connecticut 06511, USA
| | - Michel H Devoret
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06511, USA; Yale Quantum Institute, Yale University, New Haven, Connecticut 06511, USA
| | - S M Girvin
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06511, USA; Yale Quantum Institute, Yale University, New Haven, Connecticut 06511, USA
| | - Liang Jiang
- Pritzker School of Molecular Engineering, University of Chicago, Illinois 60637, USA.
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40
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Chakram S, Oriani AE, Naik RK, Dixit AV, He K, Agrawal A, Kwon H, Schuster DI. Seamless High-Q Microwave Cavities for Multimode Circuit Quantum Electrodynamics. PHYSICAL REVIEW LETTERS 2021; 127:107701. [PMID: 34533363 DOI: 10.1103/physrevlett.127.107701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 07/22/2021] [Indexed: 06/13/2023]
Abstract
Multimode cavity quantum electrodynamics-where a two-level system interacts simultaneously with many cavity modes-provides a versatile framework for quantum information processing and quantum optics. Because of the combination of long coherence times and large interaction strengths, one of the leading experimental platforms for cavity QED involves coupling a superconducting circuit to a 3D microwave cavity. In this work, we realize a 3D multimode circuit QED system with single photon lifetimes of 2 ms across 9 modes of a novel seamless cavity. We demonstrate a variety of protocols for universal single-mode quantum control applicable across all cavity modes, using only a single drive line. We achieve this by developing a straightforward flute method for creating monolithic superconducting microwave cavities that reduces loss while simultaneously allowing control of the mode spectrum and mode-qubit interaction. We highlight the flexibility and ease of implementation of this technique by using it to fabricate a variety of 3D cavity geometries, providing a template for engineering multimode quantum systems with exceptionally low dissipation. This work is an important step towards realizing hardware efficient random access quantum memories and processors, and for exploring quantum many-body physics with photons.
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Affiliation(s)
- Srivatsan Chakram
- James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Andrew E Oriani
- James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
| | - Ravi K Naik
- James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, University of California Berkeley, California 94720, USA
| | - Akash V Dixit
- James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - Kevin He
- James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - Ankur Agrawal
- James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - Hyeokshin Kwon
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon 16678, Republic of Korea
| | - David I Schuster
- James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
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41
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Cai W, Han J, Hu L, Ma Y, Mu X, Wang W, Xu Y, Hua Z, Wang H, Song YP, Zhang JN, Zou CL, Sun L. High-Efficiency Arbitrary Quantum Operation on a High-Dimensional Quantum System. PHYSICAL REVIEW LETTERS 2021; 127:090504. [PMID: 34506165 DOI: 10.1103/physrevlett.127.090504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 08/02/2021] [Indexed: 06/13/2023]
Abstract
The ability to manipulate quantum systems lies at the heart of the development of quantum technology. The ultimate goal of quantum control is to realize arbitrary quantum operations (AQUOs) for all possible open quantum system dynamics. However, the demanding extra physical resources impose great obstacles. Here, we experimentally demonstrate a universal approach of AQUO on a photonic qudit with the minimum physical resource of a two-level ancilla and a log_{2}d-scale circuit depth for a d-dimensional system. The AQUO is then applied in a quantum trajectory simulation for quantum subspace stabilization and quantum Zeno dynamics, as well as incoherent manipulation and generalized measurements of the qudit. Therefore, the demonstrated AQUO for complete quantum control would play an indispensable role in quantum information science.
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Affiliation(s)
- W Cai
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
| | - J Han
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
| | - L Hu
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
| | - Y Ma
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
| | - X Mu
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
| | - W Wang
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
| | - Y Xu
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
| | - Z Hua
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
| | - H Wang
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
| | - Y P Song
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
| | - J-N Zhang
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - C-L Zou
- Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - L Sun
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China
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42
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Spong NLR, Jiao Y, Hughes ODW, Weatherill KJ, Lesanovsky I, Adams CS. Collectively Encoded Rydberg Qubit. PHYSICAL REVIEW LETTERS 2021; 127:063604. [PMID: 34420315 DOI: 10.1103/physrevlett.127.063604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Accepted: 06/28/2021] [Indexed: 06/13/2023]
Abstract
We demonstrate a collectively encoded qubit based on a single Rydberg excitation stored in an ensemble of N entangled atoms. Qubit rotations are performed by applying microwave fields that drive excitations between Rydberg states. Coherent readout is performed by mapping the excitation into a single photon. Ramsey interferometry is used to probe the coherence of the qubit, as well as to test the robustness to external perturbations. We show that qubit coherence is preserved even as we lose atoms from the polariton mode, preserving Ramsey fringe visibility. We show that dephasing due to electric field noise scales as the fourth power of field amplitude. These results show that robust quantum information processing can be achieved via collective encoding using Rydberg polaritons, and hence this system could provide an attractive alternative coding strategy for quantum computation and networking.
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Affiliation(s)
- Nicholas L R Spong
- Department of Physics, Joint Quantum Centre Durham-Newcastle, Rochester Building, Durham, England DH1 3LE, United Kingdom
| | - Yuechun Jiao
- Department of Physics, Joint Quantum Centre Durham-Newcastle, Rochester Building, Durham, England DH1 3LE, United Kingdom
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan 030006, China
| | - Oliver D W Hughes
- Department of Physics, Joint Quantum Centre Durham-Newcastle, Rochester Building, Durham, England DH1 3LE, United Kingdom
| | - Kevin J Weatherill
- Department of Physics, Joint Quantum Centre Durham-Newcastle, Rochester Building, Durham, England DH1 3LE, United Kingdom
| | - Igor Lesanovsky
- Institut für Theoretische Physik, Auf der Morgenstelle 14, 72076 Tübingen, Germany
- School of Physics and Astronomy and Centre for the Mathematics and Theoretical Physics of Quantum Non-Equilibrium Systems, The University of Nottingham, Nottingham, England NG7 2RD, United Kingdom
| | - Charles S Adams
- Department of Physics, Joint Quantum Centre Durham-Newcastle, Rochester Building, Durham, England DH1 3LE, United Kingdom
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43
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Zhang DB, Zhang GQ, Xue ZY, Zhu SL, Wang ZD. Continuous-Variable Assisted Thermal Quantum Simulation. PHYSICAL REVIEW LETTERS 2021; 127:020502. [PMID: 34296925 DOI: 10.1103/physrevlett.127.020502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 11/30/2020] [Accepted: 06/10/2021] [Indexed: 06/13/2023]
Abstract
Simulation of a quantum many-body system at finite temperatures is crucially important but quite challenging. Here we present an experimentally feasible quantum algorithm assisted with continuous variable for simulating quantum systems at finite temperatures. Our algorithm has a time complexity scaling polynomially with the inverse temperature and the desired accuracy. We demonstrate the quantum algorithm by simulating a finite temperature phase diagram of the quantum Ising and Kitaev models. It is found that the important crossover phase diagram of the Kitaev ring can be accurately simulated by a quantum computer with only a few qubits and thus the algorithm may be implementable on current quantum processors. We further propose a protocol with superconducting or trapped ion quantum computers.
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Affiliation(s)
- Dan-Bo Zhang
- Guangdong-Hong Kong Joint Laboratory of Quantum Matter, Frontier Research Institute for Physics, South China Normal University, Guangzhou 510006, China
- Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006, China
| | - Guo-Qing Zhang
- Guangdong-Hong Kong Joint Laboratory of Quantum Matter, Frontier Research Institute for Physics, South China Normal University, Guangzhou 510006, China
- Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006, China
| | - Zheng-Yuan Xue
- Guangdong-Hong Kong Joint Laboratory of Quantum Matter, Frontier Research Institute for Physics, South China Normal University, Guangzhou 510006, China
- Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006, China
| | - Shi-Liang Zhu
- Guangdong-Hong Kong Joint Laboratory of Quantum Matter, Frontier Research Institute for Physics, South China Normal University, Guangzhou 510006, China
- Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006, China
| | - Z D Wang
- Guangdong-Hong Kong Joint Laboratory of Quantum Matter, Department of Physics, and HKU-UCAS Joint Institute for Theoretical and Computational Physics at Hong Kong, The University of Hong Kong, Pokfulam Road, Hong Kong, China
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44
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Gross JA. Designing Codes around Interactions: The Case of a Spin. PHYSICAL REVIEW LETTERS 2021; 127:010504. [PMID: 34270305 DOI: 10.1103/physrevlett.127.010504] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 05/18/2021] [Indexed: 06/13/2023]
Abstract
I present a new approach for designing quantum error-correcting codes guaranteeing a physically natural implementation of Clifford operations. Inspired by the scheme put forward by Gottesman, Kitaev, and Preskill for encoding a qubit in an oscillator in which Clifford operations may be performed via Gaussian unitaries, this approach yields new schemes for encoding a qubit in a large spin in which single-qubit Clifford operations may be performed via spatial rotations. I construct all possible examples of such codes, provide universal-gate-set implementations using quadratic angular-momentum Hamiltonians, and derive criteria for when these codes exactly correct physically relevant errors.
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Affiliation(s)
- Jonathan A Gross
- Institut quantique et Départment de Physique, Université de Sherbrooke, Québec J1K 2R1, Canada
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45
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Lu Y, Strandberg I, Quijandría F, Johansson G, Gasparinetti S, Delsing P. Propagating Wigner-Negative States Generated from the Steady-State Emission of a Superconducting Qubit. PHYSICAL REVIEW LETTERS 2021; 126:253602. [PMID: 34241509 DOI: 10.1103/physrevlett.126.253602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 06/01/2021] [Indexed: 06/13/2023]
Abstract
We experimentally demonstrate the steady-state generation of propagating Wigner-negative states from a continuously driven superconducting qubit. We reconstruct the Wigner function of the radiation emitted into propagating modes defined by their temporal envelopes, using digital filtering. For an optimized temporal filter, we observe a large Wigner logarithmic negativity, in excess of 0.08, in agreement with theory. The fidelity between the theoretical predictions and the states generated experimentally is up to 99%, reaching state-of-the-art realizations in the microwave frequency domain. Our results provide a new way to generate and control nonclassical states, and may enable promising applications such as quantum networks and quantum computation based on waveguide quantum electrodynamics.
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Affiliation(s)
- Yong Lu
- Department of Microtechnology and Nanoscience MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - Ingrid Strandberg
- Department of Microtechnology and Nanoscience MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - Fernando Quijandría
- Department of Microtechnology and Nanoscience MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - Göran Johansson
- Department of Microtechnology and Nanoscience MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - Simone Gasparinetti
- Department of Microtechnology and Nanoscience MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - Per Delsing
- Department of Microtechnology and Nanoscience MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
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46
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Keller J, Hou PY, McCormick KC, Cole DC, Erickson SD, Wu JJ, Wilson AC, Leibfried D. Quantum Harmonic Oscillator Spectrum Analyzers. PHYSICAL REVIEW LETTERS 2021; 126:250507. [PMID: 34241508 PMCID: PMC10807510 DOI: 10.1103/physrevlett.126.250507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 04/08/2021] [Indexed: 06/13/2023]
Abstract
Characterization and suppression of noise are essential for the control of harmonic oscillators in the quantum regime. We measure the noise spectrum of a quantum harmonic oscillator from low frequency to near the oscillator resonance by sensing its response to amplitude modulated periodic drives with a qubit. Using the motion of a trapped ion, we experimentally demonstrate two different implementations with combined sensitivity to noise from 500 Hz to 600 kHz. We apply our method to measure the intrinsic noise spectrum of an ion trap potential in a previously unaccessed frequency range.
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Affiliation(s)
- Jonas Keller
- 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
| | - Katherine C McCormick
- 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
| | - 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
| | - 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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Milne AR, Hempel C, Li L, Edmunds CL, Slatyer HJ, Ball H, Hush MR, Biercuk MJ. Quantum Oscillator Noise Spectroscopy via Displaced Cat States. PHYSICAL REVIEW LETTERS 2021; 126:250506. [PMID: 34241523 DOI: 10.1103/physrevlett.126.250506] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 04/21/2021] [Indexed: 06/13/2023]
Abstract
Quantum harmonic oscillators are central to many modern quantum technologies. We introduce a method to determine the frequency noise spectrum of oscillator modes through coupling them to a qubit with continuously driven qubit-state-dependent displacements. We reconstruct the noise spectrum using a series of different drive phase and amplitude modulation patterns in conjunction with a data-fusion routine based on convex optimization. We apply the technique to the identification of intrinsic noise in the motional frequency of a single trapped ion with sensitivity to fluctuations at the sub-Hz level in a spectral range from quasi-dc up to 50 kHz.
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Affiliation(s)
- Alistair R Milne
- ARC Centre of Excellence for Engineered Quantum Systems, The University of Sydney, School of Physics, New South Wales 2006, Australia
| | - Cornelius Hempel
- ARC Centre of Excellence for Engineered Quantum Systems, The University of Sydney, School of Physics, New South Wales 2006, Australia
| | - Li Li
- Q-CTRL Pty Ltd, Sydney, New South Wales 2006, Australia
| | - Claire L Edmunds
- ARC Centre of Excellence for Engineered Quantum Systems, The University of Sydney, School of Physics, New South Wales 2006, Australia
| | | | - Harrison Ball
- Q-CTRL Pty Ltd, Sydney, New South Wales 2006, Australia
| | | | - Michael J Biercuk
- ARC Centre of Excellence for Engineered Quantum Systems, The University of Sydney, School of Physics, New South Wales 2006, Australia
- Q-CTRL Pty Ltd, Sydney, New South Wales 2006, Australia
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Hastrup J, Park K, Filip R, Andersen UL. Unconditional Preparation of Squeezed Vacuum from Rabi Interactions. PHYSICAL REVIEW LETTERS 2021; 126:153602. [PMID: 33929221 DOI: 10.1103/physrevlett.126.153602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 03/01/2021] [Indexed: 06/12/2023]
Abstract
Squeezed states of harmonic oscillators are a central resource for continuous-variable quantum sensing, computation, and communication. Here, we propose a method for the generation of very good approximations to highly squeezed vacuum states with low excess antisqueezing using only a few oscillator-qubit coupling gates through a Rabi-type interaction Hamiltonian. This interaction can be implemented with several different methods, which has previously been demonstrated in superconducting circuit and trapped-ion platforms. The protocol is compatible with other protocols manipulating quantum harmonic oscillators, thus facilitating scalable continuous-variable fault-tolerant quantum computation.
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Affiliation(s)
- Jacob Hastrup
- Center for Macroscopic Quantum States (bigQ), Department of Physics, Technical University of Denmark, Building 307, Fysikvej, 2800 Kongens Lyngby, Denmark
| | - Kimin Park
- Center for Macroscopic Quantum States (bigQ), Department of Physics, Technical University of Denmark, Building 307, Fysikvej, 2800 Kongens Lyngby, Denmark
- Department of Optics, Palacky University, 77146 Olomouc, Czech Republic
| | - Radim Filip
- Department of Optics, Palacky University, 77146 Olomouc, Czech Republic
| | - Ulrik Lund Andersen
- Center for Macroscopic Quantum States (bigQ), Department of Physics, Technical University of Denmark, Building 307, Fysikvej, 2800 Kongens Lyngby, Denmark
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Cai W, Ma Y, Wang W, Zou CL, Sun L. Bosonic quantum error correction codes in superconducting quantum circuits. FUNDAMENTAL RESEARCH 2021. [DOI: 10.1016/j.fmre.2020.12.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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