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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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Lledó C, Dassonneville R, Moulinas A, Cohen J, Shillito R, Bienfait A, Huard B, Blais A. Cloaking a qubit in a cavity. Nat Commun 2023; 14:6313. [PMID: 37813905 PMCID: PMC10562410 DOI: 10.1038/s41467-023-42060-5] [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: 08/16/2023] [Accepted: 09/28/2023] [Indexed: 10/11/2023] Open
Abstract
Cavity quantum electrodynamics (QED) uses a cavity to engineer the mode structure of the vacuum electromagnetic field such as to enhance the interaction between light and matter. Exploiting these ideas in solid-state systems has lead to circuit QED which has emerged as a valuable tool to explore the rich physics of quantum optics and as a platform for quantum computation. Here we introduce a simple approach to further engineer the light-matter interaction in a driven cavity by controllably decoupling a qubit from the cavity's photon population, effectively cloaking the qubit from the cavity. This is realized by driving the qubit with an external tone tailored to destructively interfere with the cavity field, leaving the qubit to interact with a cavity which appears to be in the vacuum state. Our experiment demonstrates how qubit cloaking can be exploited to cancel the ac-Stark shift and measurement-induced dephasing, and to accelerate qubit readout. In addition to qubit readout, applications of this method include qubit logical operations and the preparation of non-classical cavity states in circuit QED and other cavity-based setups.
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Affiliation(s)
- Cristóbal Lledó
- Institut Quantique and Département de Physique, Université de Sherbrooke, Sherbrooke, J1K 2R1 QC, Canada.
| | - Rémy Dassonneville
- Ecole Normale Supérieure de Lyon, CNRS, Laboratoire de Physique, F-69342, Lyon, France
| | - Adrien Moulinas
- Institut Quantique and Département de Physique, Université de Sherbrooke, Sherbrooke, J1K 2R1 QC, Canada
| | - Joachim Cohen
- Institut Quantique and Département de Physique, Université de Sherbrooke, Sherbrooke, J1K 2R1 QC, Canada
| | - Ross Shillito
- Institut Quantique and Département de Physique, Université de Sherbrooke, Sherbrooke, J1K 2R1 QC, Canada
| | - Audrey Bienfait
- Ecole Normale Supérieure de Lyon, CNRS, Laboratoire de Physique, F-69342, Lyon, France
| | - Benjamin Huard
- Ecole Normale Supérieure de Lyon, CNRS, Laboratoire de Physique, F-69342, Lyon, France
| | - Alexandre Blais
- Institut Quantique and Département de Physique, Université de Sherbrooke, Sherbrooke, J1K 2R1 QC, Canada
- Canadian Institute for Advanced Research, Toronto, ON, M5G1M1, Canada
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Arrachea L. Energy dynamics, heat production and heat-work conversion with qubits: toward the development of quantum machines. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2023; 86:036501. [PMID: 36603220 DOI: 10.1088/1361-6633/acb06b] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 01/05/2023] [Indexed: 06/17/2023]
Abstract
We present an overview of recent advances in the study of energy dynamics and mechanisms for energy conversion in qubit systems with special focus on realizations in superconducting quantum circuits. We briefly introduce the relevant theoretical framework to analyze heat generation, energy transport and energy conversion in these systems with and without time-dependent driving considering the effect of equilibrium and non-equilibrium environments. We analyze specific problems and mechanisms under current investigation in the context of qubit systems. These include the problem of energy dissipation and possible routes for its control, energy pumping between driving sources and heat pumping between reservoirs, implementation of thermal machines and mechanisms for energy storage. We highlight the underlying fundamental phenomena related to geometrical and topological properties, as well as many-body correlations. We also present an overview of recent experimental activity in this field.
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Affiliation(s)
- Liliana Arrachea
- Escuela de Ciencia y Tecnología and ICIFI, Universidad de San Martín, Av. 25 de Mayo y Francia, 1650 Buenos Aires, Argentina
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Qin W, Miranowicz A, Nori F. Beating the 3 dB Limit for Intracavity Squeezing and Its Application to Nondemolition Qubit Readout. PHYSICAL REVIEW LETTERS 2022; 129:123602. [PMID: 36179165 DOI: 10.1103/physrevlett.129.123602] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Accepted: 08/22/2022] [Indexed: 06/16/2023]
Abstract
While the squeezing of a propagating field can, in principle, be made arbitrarily strong, the cavity-field squeezing is subject to the well-known 3 dB limit, and thus has limited applications. Here, we propose the use of a fully quantum degenerate parametric amplifier (DPA) to beat this squeezing limit. Specifically, we show that by simply applying a two-tone driving to the signal mode, the pump mode can, counterintuitively, be driven by the photon loss of the signal mode into a squeezed steady state with, in principle, an arbitrarily high degree of squeezing. Furthermore, we demonstrate that this intracavity squeezing can increase the signal-to-noise ratio of longitudinal qubit readout exponentially with the degree of squeezing. Correspondingly, an improvement of the measurement error by many orders of magnitude can be achieved even for modest parameters. In stark contrast, using intracavity squeezing of the semiclassical DPA cannot practically increase the signal-to-noise ratio and thus improve the measurement error. Our results extend the range of applications of DPAs and open up new opportunities for modern quantum technologies.
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Affiliation(s)
- Wei Qin
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
| | - Adam Miranowicz
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
- Institute of Spintronics and Quantum Information, Faculty of Physics, Adam Mickiewicz University 61-614 Poznań, Poland
| | - Franco Nori
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
- RIKEN Center for Quantum Computing, Wako-shi, Saitama 351-0198, Japan
- Department of Physics, The University of Michigan, Ann Arbor, Michigan 48109-1040, USA
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5
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Bolometer operating at the threshold for circuit quantum electrodynamics. Nature 2020; 586:47-51. [PMID: 32999484 DOI: 10.1038/s41586-020-2753-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 08/18/2020] [Indexed: 11/08/2022]
Abstract
Radiation sensors based on the heating effect of absorbed radiation are typically simple to operate and flexible in terms of input frequency, so they are widely used in gas detection1, security2, terahertz imaging3, astrophysical observations4 and medical applications5. Several important applications are currently emerging from quantum technology and especially from electrical circuits that behave quantum mechanically, that is, circuit quantum electrodynamics6. This field has given rise to single-photon microwave detectors7-9 and a quantum computer that is superior to classical supercomputers for certain tasks10. Thermal sensors hold potential for enhancing such devices because they do not add quantum noise and they are smaller, simpler and consume about six orders of magnitude less power than the frequently used travelling-wave parametric amplifiers11. However, despite great progress in the speed12 and noise levels13 of thermal sensors, no bolometer has previously met the threshold for circuit quantum electrodynamics, which lies at a time constant of a few hundred nanoseconds and a simultaneous energy resolution of the order of 10h gigahertz (where h is the Planck constant). Here we experimentally demonstrate a bolometer that operates at this threshold, with a noise-equivalent power of 30 zeptowatts per square-root hertz, comparable to the lowest value reported so far13, at a thermal time constant two orders of magnitude shorter, at 500 nanoseconds. Both of these values are measured directly on the same device, giving an accurate estimation of 30h gigahertz for the calorimetric energy resolution. These improvements stem from the use of a graphene monolayer with extremely low specific heat14 as the active material. The minimum observed time constant of 200 nanoseconds is well below the dephasing times of roughly 100 microseconds reported for superconducting qubits15 and matches the timescales of currently used readout schemes16,17, thus enabling circuit quantum electrodynamics applications for bolometers.
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Peronnin T, Marković D, Ficheux Q, Huard B. Sequential Dispersive Measurement of a Superconducting Qubit. PHYSICAL REVIEW LETTERS 2020; 124:180502. [PMID: 32441960 DOI: 10.1103/physrevlett.124.180502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 04/13/2020] [Indexed: 06/11/2023]
Abstract
We present a superconducting device that realizes the sequential measurement of a transmon qubit. The device disables common limitations of dispersive readout such as Purcell effect or transients in the cavity mode by turning on and off the coupling to the measurement channel on demand. The qubit measurement begins by loading a readout resonator that is coupled to the qubit. After an optimal interaction time with negligible loss, a microwave pump releases the content of the readout mode by upconversion into a measurement line in a characteristic time as low as 10 ns, which is 400 times shorter than the lifetime of the readout resonator. A direct measurement of the released field quadratures demonstrates a readout fidelity of 97.5% in a total measurement time of 220 ns. The Wigner tomography of the readout mode allows us to characterize the non-Gaussian nature of the readout mode and its dynamics.
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Affiliation(s)
- T Peronnin
- Université Lyon, ENS de Lyon, Université Claude Bernard Lyon 1, CNRS, Laboratoire de Physique, F-69342 Lyon, France
| | - D Marković
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - Q Ficheux
- Université Lyon, ENS de Lyon, Université Claude Bernard Lyon 1, CNRS, Laboratoire de Physique, F-69342 Lyon, France
| | - B Huard
- Université Lyon, ENS de Lyon, Université Claude Bernard Lyon 1, CNRS, Laboratoire de Physique, F-69342 Lyon, France
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Touzard S, Kou A, Frattini NE, Sivak VV, Puri S, Grimm A, Frunzio L, Shankar S, Devoret MH. Gated Conditional Displacement Readout of Superconducting Qubits. PHYSICAL REVIEW LETTERS 2019; 122:080502. [PMID: 30932609 DOI: 10.1103/physrevlett.122.080502] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Indexed: 06/09/2023]
Abstract
We have realized a new interaction between superconducting qubits and a readout cavity that results in the displacement of a coherent state in the cavity, conditioned on the state of the qubit. This conditional state, when it reaches the cavity-following, phase-sensitive amplifier, matches its measured observable, namely, the in phase quadrature. In a setup where several qubits are coupled to the same readout resonator, we show it is possible to measure the state of a target qubit with minimal dephasing of the other qubits. Our results suggest novel directions for faster readout of superconducting qubits and implementations of bosonic quantum error-correcting codes.
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Affiliation(s)
- S Touzard
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - A Kou
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - N E Frattini
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - V V Sivak
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - S Puri
- Yale Quantum Institute, Yale University, New Haven, Connecticut 06520, USA
| | - A Grimm
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - L Frunzio
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - S Shankar
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - M H Devoret
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
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