1
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Khandelwal S, Chen W, Murch KW, Haack G. Chiral Bell-State Transfer via Dissipative Liouvillian Dynamics. PHYSICAL REVIEW LETTERS 2024; 133:070403. [PMID: 39213564 DOI: 10.1103/physrevlett.133.070403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 06/06/2024] [Indexed: 09/04/2024]
Abstract
Chiral state transfer along closed loops in the vicinity of an exceptional point is one of the many counterintuitive observations in non-Hermitian physics. The application of this property beyond proof-of-principle in quantum physics, is an open question. In this work, we demonstrate chiral state conversion between singlet and triplet Bell states through fully quantum Liouvillian dynamics. Crucially, we demonstrate that this property can be used for the chiral production of Bell states from separable states with a high fidelity and for a large range of parameters. Additionally, we show that the removal of quantum jumps from the dynamics through postselection can result in near-perfect Bell states from initially separable states. Our work presents the first application of chiral state transfer in quantum information processing and demonstrates a novel way to control entangled states by means of dissipation engineering.
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Affiliation(s)
- Shishir Khandelwal
- Department of Applied Physics, University of Geneva, 1211 Geneva, Switzerland
- Physics Department, Lund University, Box 118, 22100 Lund, Sweden
- NanoLund, Lund University, Box 118, 22100 Lund, Sweden
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2
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Gaikwad C, Kowsari D, Brame C, Song X, Zhang H, Esposito M, Ranadive A, Cappelli G, Roch N, Levenson-Falk EM, Murch KW. Entanglement Assisted Probe of the Non-Markovian to Markovian Transition in Open Quantum System Dynamics. PHYSICAL REVIEW LETTERS 2024; 132:200401. [PMID: 38829081 DOI: 10.1103/physrevlett.132.200401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 04/16/2024] [Indexed: 06/05/2024]
Abstract
We utilize a superconducting qubit processor to experimentally probe non-Markovian dynamics of an entangled qubit pair. We prepare an entangled state between two qubits and monitor the evolution of entanglement over time as one of the qubits interacts with a small quantum environment consisting of an auxiliary transmon qubit coupled to its readout cavity. We observe the collapse and revival of the entanglement as a signature of quantum memory effects in the environment. We then engineer the non-Markovianity of the environment by populating its readout cavity with thermal photons to show a transition from non-Markovian to Markovian dynamics, ultimately reaching a regime where the quantum Zeno effect creates a decoherence-free subspace that effectively stabilizes the entanglement between the qubits.
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Affiliation(s)
| | - Daria Kowsari
- Department of Physics, Washington University, St. Louis, Missouri 63130, USA
- Center for Quantum Information Science and Technology, University of Southern California, Los Angeles, California 90089, USA
- Department of Physics & Astronomy, University of Southern California, Los Angeles, California 90089, USA
| | - Carson Brame
- Department of Physics, Washington University, St. Louis, Missouri 63130, USA
| | - Xingrui Song
- Department of Physics, Washington University, St. Louis, Missouri 63130, USA
| | - Haimeng Zhang
- Center for Quantum Information Science and Technology, University of Southern California, Los Angeles, California 90089, USA
- Ming Hsieh Department of Electrical & Computer Engineering, University of Southern California, Los Angeles, California 90089, USA
| | - Martina Esposito
- CNR-SPIN Complesso di Monte S. Angelo, via Cintia, Napoli 80126, Italy
| | - Arpit Ranadive
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France
| | - Giulio Cappelli
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France
| | - Nicolas Roch
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France
| | - Eli M Levenson-Falk
- Center for Quantum Information Science and Technology, University of Southern California, Los Angeles, California 90089, USA
- Department of Physics & Astronomy, University of Southern California, Los Angeles, California 90089, USA
- Ming Hsieh Department of Electrical & Computer Engineering, University of Southern California, Los Angeles, California 90089, USA
| | - Kater W Murch
- Department of Physics, Washington University, St. Louis, Missouri 63130, USA
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3
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Li S, Ni Z, Zhang L, Cai Y, Mai J, Wen S, Zheng P, Deng X, Liu S, Xu Y, Yu D. Autonomous Stabilization of Fock States in an Oscillator against Multiphoton Losses. PHYSICAL REVIEW LETTERS 2024; 132:203602. [PMID: 38829095 DOI: 10.1103/physrevlett.132.203602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 04/23/2024] [Indexed: 06/05/2024]
Abstract
Fock states with a well-defined number of photons in an oscillator have shown a wide range of applications in quantum information science. Nonetheless, their usefulness has been marred by single and multiphoton losses due to unavoidable environment-induced dissipation. Though several dissipation engineering methods have been developed to counteract the leading single-photon-loss error, averting multiple-photon losses remains elusive. Here, we experimentally demonstrate a dissipation engineering method that autonomously stabilizes multiphoton Fock states against losses of multiple photons using a cascaded selective photon-addition operation in a superconducting quantum circuit. Through measuring the photon-number populations and Wigner tomography of the oscillator states, we observe a prolonged preservation of nonclassical Wigner negativities for the stabilized Fock states |N⟩ with N=1, 2, 3 for a duration of about 10 ms. Furthermore, the dissipation engineering method demonstrated here also facilitates the implementation of a nonunitary operation for resetting a binomially encoded logical qubit. These results highlight potential applications in error-correctable quantum information processing against multiple-photon-loss errors.
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Affiliation(s)
- Sai Li
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Zhongchu Ni
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Libo Zhang
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yanyan Cai
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jiasheng Mai
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Shengcheng Wen
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Pan Zheng
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xiaowei Deng
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Song Liu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- Shenzhen Branch, Hefei National Laboratory, Shenzhen 518048, China
| | - Yuan Xu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- Shenzhen Branch, Hefei National Laboratory, Shenzhen 518048, China
| | - Dapeng Yu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
- Shenzhen Branch, Hefei National Laboratory, Shenzhen 518048, China
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4
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Mi X, Michailidis AA, Shabani S, Miao KC, Klimov PV, Lloyd J, Rosenberg E, Acharya R, Aleiner I, Andersen TI, Ansmann M, Arute F, Arya K, Asfaw A, Atalaya J, Bardin JC, Bengtsson A, Bortoli G, Bourassa A, Bovaird J, Brill L, Broughton M, Buckley BB, Buell DA, Burger T, Burkett B, Bushnell N, Chen Z, Chiaro B, Chik D, Chou C, Cogan J, Collins R, Conner P, Courtney W, Crook AL, Curtin B, Dau AG, Debroy DM, Del Toro Barba A, Demura S, Di Paolo A, Drozdov IK, Dunsworth A, Erickson C, Faoro L, Farhi E, Fatemi R, Ferreira VS, Burgos LF, Forati E, Fowler AG, Foxen B, Genois É, Giang W, Gidney C, Gilboa D, Giustina M, Gosula R, Gross JA, Habegger S, Hamilton MC, Hansen M, Harrigan MP, Harrington SD, Heu P, Hoffmann MR, Hong S, Huang T, Huff A, Huggins WJ, Ioffe LB, Isakov SV, Iveland J, Jeffrey E, Jiang Z, Jones C, Juhas P, Kafri D, Kechedzhi K, Khattar T, Khezri M, Kieferová M, Kim S, Kitaev A, Klots AR, Korotkov AN, Kostritsa F, Kreikebaum JM, Landhuis D, Laptev P, Lau KM, Laws L, Lee J, Lee KW, Lensky YD, Lester BJ, Lill AT, Liu W, Locharla A, Malone FD, Martin O, McClean JR, McEwen M, Mieszala A, Montazeri S, Morvan A, Movassagh R, Mruczkiewicz W, Neeley M, Neill C, Nersisyan A, Newman M, Ng JH, Nguyen A, Nguyen M, Niu MY, O'Brien TE, Opremcak A, Petukhov A, Potter R, Pryadko LP, Quintana C, Rocque C, Rubin NC, Saei N, Sank D, Sankaragomathi K, Satzinger KJ, Schurkus HF, Schuster C, Shearn MJ, Shorter A, Shutty N, Shvarts V, Skruzny J, Smith WC, Somma R, Sterling G, Strain D, Szalay M, Torres A, Vidal G, Villalonga B, Heidweiller CV, White T, Woo BWK, Xing C, Yao ZJ, Yeh P, Yoo J, Young G, Zalcman A, Zhang Y, Zhu N, Zobrist N, Neven H, Babbush R, Bacon D, Boixo S, Hilton J, Lucero E, Megrant A, Kelly J, Chen Y, Roushan P, Smelyanskiy V, Abanin DA. Stable quantum-correlated many-body states through engineered dissipation. Science 2024; 383:1332-1337. [PMID: 38513021 DOI: 10.1126/science.adh9932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 02/13/2024] [Indexed: 03/23/2024]
Abstract
Engineered dissipative reservoirs have the potential to steer many-body quantum systems toward correlated steady states useful for quantum simulation of high-temperature superconductivity or quantum magnetism. Using up to 49 superconducting qubits, we prepared low-energy states of the transverse-field Ising model through coupling to dissipative auxiliary qubits. In one dimension, we observed long-range quantum correlations and a ground-state fidelity of 0.86 for 18 qubits at the critical point. In two dimensions, we found mutual information that extends beyond nearest neighbors. Lastly, by coupling the system to auxiliaries emulating reservoirs with different chemical potentials, we explored transport in the quantum Heisenberg model. Our results establish engineered dissipation as a scalable alternative to unitary evolution for preparing entangled many-body states on noisy quantum processors.
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Affiliation(s)
- X Mi
- Google Research, Mountain View, CA, USA
| | - A A Michailidis
- Department of Theoretical Physics, University of Geneva, Geneva, Switzerland
| | - S Shabani
- Google Research, Mountain View, CA, USA
| | - K C Miao
- Google Research, Mountain View, CA, USA
| | | | - J Lloyd
- Department of Theoretical Physics, University of Geneva, Geneva, Switzerland
| | | | - R Acharya
- Google Research, Mountain View, CA, USA
| | - I Aleiner
- Google Research, Mountain View, CA, USA
| | | | - M Ansmann
- Google Research, Mountain View, CA, USA
| | - F Arute
- Google Research, Mountain View, CA, USA
| | - K Arya
- Google Research, Mountain View, CA, USA
| | - A Asfaw
- Google Research, Mountain View, CA, USA
| | - J Atalaya
- Google Research, Mountain View, CA, USA
| | - J C Bardin
- Google Research, Mountain View, CA, USA
- Department of Electrical and Computer Engineering, University of Massachusetts, Amherst, MA, USA
| | | | - G Bortoli
- Google Research, Mountain View, CA, USA
| | | | - J Bovaird
- Google Research, Mountain View, CA, USA
| | - L Brill
- Google Research, Mountain View, CA, USA
| | | | | | - D A Buell
- Google Research, Mountain View, CA, USA
| | - T Burger
- Google Research, Mountain View, CA, USA
| | - B Burkett
- Google Research, Mountain View, CA, USA
| | | | - Z Chen
- Google Research, Mountain View, CA, USA
| | - B Chiaro
- Google Research, Mountain View, CA, USA
| | - D Chik
- Google Research, Mountain View, CA, USA
| | - C Chou
- Google Research, Mountain View, CA, USA
| | - J Cogan
- Google Research, Mountain View, CA, USA
| | - R Collins
- Google Research, Mountain View, CA, USA
| | - P Conner
- Google Research, Mountain View, CA, USA
| | | | - A L Crook
- Google Research, Mountain View, CA, USA
| | - B Curtin
- Google Research, Mountain View, CA, USA
| | - A G Dau
- Google Research, Mountain View, CA, USA
| | | | | | - S Demura
- Google Research, Mountain View, CA, USA
| | | | | | | | | | - L Faoro
- Google Research, Mountain View, CA, USA
| | - E Farhi
- Google Research, Mountain View, CA, USA
| | - R Fatemi
- Google Research, Mountain View, CA, USA
| | | | | | - E Forati
- Google Research, Mountain View, CA, USA
| | | | - B Foxen
- Google Research, Mountain View, CA, USA
| | - É Genois
- Google Research, Mountain View, CA, USA
| | - W Giang
- Google Research, Mountain View, CA, USA
| | - C Gidney
- Google Research, Mountain View, CA, USA
| | - D Gilboa
- Google Research, Mountain View, CA, USA
| | | | - R Gosula
- Google Research, Mountain View, CA, USA
| | - J A Gross
- Google Research, Mountain View, CA, USA
| | | | - M C Hamilton
- Google Research, Mountain View, CA, USA
- Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, USA
| | - M Hansen
- Google Research, Mountain View, CA, USA
| | | | | | - P Heu
- Google Research, Mountain View, CA, USA
| | | | - S Hong
- Google Research, Mountain View, CA, USA
| | - T Huang
- Google Research, Mountain View, CA, USA
| | - A Huff
- Google Research, Mountain View, CA, USA
| | | | - L B Ioffe
- Google Research, Mountain View, CA, USA
| | | | - J Iveland
- Google Research, Mountain View, CA, USA
| | - E Jeffrey
- Google Research, Mountain View, CA, USA
| | - Z Jiang
- Google Research, Mountain View, CA, USA
| | - C Jones
- Google Research, Mountain View, CA, USA
| | - P Juhas
- Google Research, Mountain View, CA, USA
| | - D Kafri
- Google Research, Mountain View, CA, USA
| | | | - T Khattar
- Google Research, Mountain View, CA, USA
| | - M Khezri
- Google Research, Mountain View, CA, USA
| | - M Kieferová
- Google Research, Mountain View, CA, USA
- Centre for Quantum Software and Information (QSI), Faculty of Engineering and Information Technology, University of Technology Sydney, Sydney, NSW, Australia
| | - S Kim
- Google Research, Mountain View, CA, USA
| | - A Kitaev
- Google Research, Mountain View, CA, USA
| | - A R Klots
- Google Research, Mountain View, CA, USA
| | - A N Korotkov
- Google Research, Mountain View, CA, USA
- Department of Electrical and Computer Engineering, University of California, Riverside, CA, USA
| | | | | | | | - P Laptev
- Google Research, Mountain View, CA, USA
| | - K-M Lau
- Google Research, Mountain View, CA, USA
| | - L Laws
- Google Research, Mountain View, CA, USA
| | - J Lee
- Google Research, Mountain View, CA, USA
- Department of Chemistry, Columbia University, New York, NY, USA
| | - K W Lee
- Google Research, Mountain View, CA, USA
| | | | | | - A T Lill
- Google Research, Mountain View, CA, USA
| | - W Liu
- Google Research, Mountain View, CA, USA
| | | | | | - O Martin
- Google Research, Mountain View, CA, USA
| | | | - M McEwen
- Google Research, Mountain View, CA, USA
| | | | | | - A Morvan
- Google Research, Mountain View, CA, USA
| | | | | | - M Neeley
- Google Research, Mountain View, CA, USA
| | - C Neill
- Google Research, Mountain View, CA, USA
| | | | - M Newman
- Google Research, Mountain View, CA, USA
| | - J H Ng
- Google Research, Mountain View, CA, USA
| | - A Nguyen
- Google Research, Mountain View, CA, USA
| | - M Nguyen
- Google Research, Mountain View, CA, USA
| | - M Y Niu
- Google Research, Mountain View, CA, USA
| | | | | | | | - R Potter
- Google Research, Mountain View, CA, USA
| | - L P Pryadko
- Google Research, Mountain View, CA, USA
- Department of Physics and Astronomy, University of California, Riverside, CA, USA
| | | | - C Rocque
- Google Research, Mountain View, CA, USA
| | - N C Rubin
- Google Research, Mountain View, CA, USA
| | - N Saei
- Google Research, Mountain View, CA, USA
| | - D Sank
- Google Research, Mountain View, CA, USA
| | | | | | | | | | | | - A Shorter
- Google Research, Mountain View, CA, USA
| | - N Shutty
- Google Research, Mountain View, CA, USA
| | - V Shvarts
- Google Research, Mountain View, CA, USA
| | - J Skruzny
- Google Research, Mountain View, CA, USA
| | - W C Smith
- Google Research, Mountain View, CA, USA
| | - R Somma
- Google Research, Mountain View, CA, USA
| | | | - D Strain
- Google Research, Mountain View, CA, USA
| | - M Szalay
- Google Research, Mountain View, CA, USA
| | - A Torres
- Google Research, Mountain View, CA, USA
| | - G Vidal
- Google Research, Mountain View, CA, USA
| | | | | | - T White
- Google Research, Mountain View, CA, USA
| | - B W K Woo
- Google Research, Mountain View, CA, USA
| | - C Xing
- Google Research, Mountain View, CA, USA
| | - Z J Yao
- Google Research, Mountain View, CA, USA
| | - P Yeh
- Google Research, Mountain View, CA, USA
| | - J Yoo
- Google Research, Mountain View, CA, USA
| | - G Young
- Google Research, Mountain View, CA, USA
| | - A Zalcman
- Google Research, Mountain View, CA, USA
| | - Y Zhang
- Google Research, Mountain View, CA, USA
| | - N Zhu
- Google Research, Mountain View, CA, USA
| | - N Zobrist
- Google Research, Mountain View, CA, USA
| | - H Neven
- Google Research, Mountain View, CA, USA
| | - R Babbush
- Google Research, Mountain View, CA, USA
| | - D Bacon
- Google Research, Mountain View, CA, USA
| | - S Boixo
- Google Research, Mountain View, CA, USA
| | - J Hilton
- Google Research, Mountain View, CA, USA
| | - E Lucero
- Google Research, Mountain View, CA, USA
| | - A Megrant
- Google Research, Mountain View, CA, USA
| | - J Kelly
- Google Research, Mountain View, CA, USA
| | - Y Chen
- Google Research, Mountain View, CA, USA
| | - P Roushan
- Google Research, Mountain View, CA, USA
| | | | - D A Abanin
- Google Research, Mountain View, CA, USA
- Department of Theoretical Physics, University of Geneva, Geneva, Switzerland
- Department of Physics, Princeton University, Princeton, NJ, USA
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5
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Song X, Murch K. Parity-Time Symmetric Holographic Principle. ENTROPY (BASEL, SWITZERLAND) 2023; 25:1523. [PMID: 37998215 PMCID: PMC10670666 DOI: 10.3390/e25111523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 10/27/2023] [Accepted: 11/01/2023] [Indexed: 11/25/2023]
Abstract
Originating from the Hamiltonian of a single qubit system, the phenomenon of the avoided level crossing is ubiquitous in multiple branches of physics, including the Landau-Zener transition in atomic, molecular, and optical physics, the band structure of condensed matter physics and the dispersion relation of relativistic quantum physics. We revisit this fundamental phenomenon in the simple example of a spinless relativistic quantum particle traveling in (1+1)-dimensional space-time and establish its relation to a spin-1/2 system evolving under a PT-symmetric Hamiltonian. This relation allows us to simulate 1-dimensional eigenvalue problems with a single qubit. Generalizing this relation to the eigenenergy problem of a bulk system with N spatial dimensions reveals that its eigenvalue problem can be mapped onto the time evolution of the edge state with (N-1) spatial dimensions governed by a non-Hermitian Hamiltonian. In other words, the bulk eigenenergy state is encoded in the edge state as a hologram, which can be decoded by the propagation of the edge state in the temporal dimension. We argue that the evolution will be PT-symmetric as long as the bulk system admits parity symmetry. Our work finds the application of PT-symmetric and non-Hermitian physics in quantum simulation and provides insights into the fundamental symmetries.
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Affiliation(s)
| | - Kater Murch
- Department of Physics, Washington University, St. Louis, MO 63130, USA;
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6
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Saha AK, Ray DS, Deb B. Phase diffusion and fluctuations in a dissipative Bose-Josephson junction. Phys Rev E 2023; 107:034141. [PMID: 37073026 DOI: 10.1103/physreve.107.034141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 03/16/2023] [Indexed: 04/20/2023]
Abstract
We analyze the phase diffusion, quantum fluctuations and their spectral features of a one-dimensional Bose-Josephson junction (BJJ) nonlinearly coupled to a bosonic heat bath. The phase diffusion is considered by taking into account of random modulations of the BJJ modes causing a phase loss of initial coherence between the ground and excited states, whereby the frequency modulation is incorporated in the system-reservoir Hamiltonian by an interaction term linear in bath operators but nonlinear in system (BJJ) operators. We examine the dependence of the phase diffusion coefficient on the on-site interaction and temperature in the zero- and π-phase modes and demonstrate its phase transition-like behavior between the Josephson oscillation and the macroscopic quantum self-trapping (MQST) regimes in the π-phase mode. Based on the thermal canonical Wigner distribution, which is the equilibrium solution of the associated quantum Langevin equation for phase, coherence factor is calculated to study phase diffusion for the zero- and π-phase modes. We investigate the quantum fluctuations of the relative phase and population imbalance in terms of fluctuation spectra which capture an interesting shift in Josephson frequency induced by frequency fluctuation due to nonlinear system-reservoir coupling, as well as the on-site interaction-induced splitting in the weak dissipative regime.
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Affiliation(s)
- Abhik Kumar Saha
- School of Physical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Deb Shankar Ray
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Bimalendu Deb
- School of Physical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
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7
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Zou CJ, Li Y, Xu JK, You JB, Png CE, Yang WL. Geometrical Bounds on Irreversibility in Squeezed Thermal Bath. ENTROPY (BASEL, SWITZERLAND) 2023; 25:128. [PMID: 36673269 PMCID: PMC9858152 DOI: 10.3390/e25010128] [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: 10/18/2022] [Revised: 12/23/2022] [Accepted: 01/05/2023] [Indexed: 06/17/2023]
Abstract
Irreversible entropy production (IEP) plays an important role in quantum thermodynamic processes. Here, we investigate the geometrical bounds of IEP in nonequilibrium thermodynamics by exemplifying a system coupled to a squeezed thermal bath subject to dissipation and dephasing, respectively. We find that the geometrical bounds of the IEP always shift in a contrary way under dissipation and dephasing, where the lower and upper bounds turning to be tighter occur in the situation of dephasing and dissipation, respectively. However, either under dissipation or under dephasing, we may reduce both the critical time of the IEP itself and the critical time of the bounds for reaching an equilibrium by harvesting the benefits of squeezing effects in which the values of the IEP, quantifying the degree of thermodynamic irreversibility, also become smaller. Therefore, due to the nonequilibrium nature of the squeezed thermal bath, the system-bath interaction energy has a prominent impact on the IEP, leading to tightness of its bounds. Our results are not contradictory with the second law of thermodynamics by involving squeezing of the bath as an available resource, which can improve the performance of quantum thermodynamic devices.
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Affiliation(s)
- Chen-Juan Zou
- Research Center of Nonlinear Science, School of Mathematical and Physical Science, Wuhan Textile University, Wuhan 430200, China
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Yue Li
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Jia-Kun Xu
- Research Center of Nonlinear Science, School of Mathematical and Physical Science, Wuhan Textile University, Wuhan 430200, China
| | - Jia-Bin You
- Institute of High Performance Computing, Agency for Science, Technology, and Research (A*STAR), 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Singapore
| | - Ching Eng Png
- Institute of High Performance Computing, Agency for Science, Technology, and Research (A*STAR), 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Singapore
| | - Wan-Li Yang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
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8
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Petiziol F, Eckardt A. Cavity-Based Reservoir Engineering for Floquet-Engineered Superconducting Circuits. PHYSICAL REVIEW LETTERS 2022; 129:233601. [PMID: 36563197 DOI: 10.1103/physrevlett.129.233601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 09/20/2022] [Accepted: 10/25/2022] [Indexed: 06/17/2023]
Abstract
Considering the example of superconducting circuits, we show how Floquet engineering can be combined with reservoir engineering for the controlled preparation of target states. Floquet engineering refers to the control of a quantum system by means of time-periodic forcing, typically in the high-frequency regime, so that the system is governed effectively by a time-independent Floquet Hamiltonian with novel interesting properties. Reservoir engineering, on the other hand, can be achieved in superconducting circuits by coupling a system of artificial atoms (or qubits) dispersively to pumped leaky cavities, so that the induced dissipation guides the system into a desired target state. It is not obvious that the two approaches can be combined, since reaching the dispersive regime, in which system and cavities exchange excitations only virtually, can be spoiled by driving-induced resonant transitions. However, working in the extended Floquet space and treating both system-cavity coupling as well as driving-induced excitation processes on the same footing perturbatively, we identify regimes, where reservoir engineering of targeted Floquet states is possible and accurately described by an effective time-independent master equation. We successfully benchmark our approach for the preparation of the ground state in a system of interacting bosons subjected to Floquet-engineered magnetic fields in different lattice geometries.
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Affiliation(s)
- Francesco Petiziol
- Technische Universität Berlin, Institut für Theoretische Physik, Hardenbergstraße 36, Berlin 10623, Germany
| | - André Eckardt
- Technische Universität Berlin, Institut für Theoretische Physik, Hardenbergstraße 36, Berlin 10623, Germany
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9
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Aiello G, Féchant M, Morvan A, Basset J, Aprili M, Gabelli J, Estève J. Quantum bath engineering of a high impedance microwave mode through quasiparticle tunneling. Nat Commun 2022; 13:7146. [PMID: 36414638 PMCID: PMC9681747 DOI: 10.1038/s41467-022-34762-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: 05/05/2022] [Accepted: 11/04/2022] [Indexed: 11/24/2022] Open
Abstract
In microwave quantum optics, dissipation usually corresponds to quantum jumps, where photons are lost one by one. Here we demonstrate a new approach to dissipation engineering. By coupling a high impedance microwave resonator to a tunnel junction, we use the photoassisted tunneling of quasiparticles as a tunable dissipative process. We are able to adjust the minimum number of lost photons per tunneling event to be one, two or more, through a dc voltage. Consequently, different Fock states of the resonator experience different loss processes. Causality then implies that each state experiences a different energy (Lamb) shift, as confirmed experimentally. This photoassisted tunneling process is analogous to a photoelectric effect, which requires a quantum description of light to be quantitatively understood. This work opens up new possibilities for quantum state manipulation in superconducting circuits, which do not rely on the Josephson effect.
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Affiliation(s)
- Gianluca Aiello
- Laboratoire de Physique des Solides, CNRS, Université Paris Saclay, Orsay, France
| | - Mathieu Féchant
- Laboratoire de Physique des Solides, CNRS, Université Paris Saclay, Orsay, France
| | - Alexis Morvan
- Laboratoire de Physique des Solides, CNRS, Université Paris Saclay, Orsay, France
| | - Julien Basset
- Laboratoire de Physique des Solides, CNRS, Université Paris Saclay, Orsay, France
| | - Marco Aprili
- Laboratoire de Physique des Solides, CNRS, Université Paris Saclay, Orsay, France
| | - Julien Gabelli
- Laboratoire de Physique des Solides, CNRS, Université Paris Saclay, Orsay, France
| | - Jérôme Estève
- Laboratoire de Physique des Solides, CNRS, Université Paris Saclay, Orsay, France.
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10
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Mylnikov VY, Potashin SO, Sokolovskii GS, Averkiev NS. Dissipative Phase Transition in Systems with Two-Photon Drive and Nonlinear Dissipation near the Critical Point. NANOMATERIALS 2022; 12:nano12152543. [PMID: 35893511 PMCID: PMC9332203 DOI: 10.3390/nano12152543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 07/15/2022] [Accepted: 07/21/2022] [Indexed: 11/16/2022]
Abstract
In this paper, we examine dissipative phase transition (DPT) near the critical point for a system with two-photon driving and nonlinear dissipations. The proposed mean-field theory, which explicitly takes into account quantum fluctuations, allowed us to describe properly the evolutionary dynamics of the system and to demonstrate new effects in its steady-state. We show that the presence of quantum fluctuations leads to a power-law dependence of the anomalous average at the phase transition point, with which the critical exponent is associated. Also, we investigate the effect of the quantum fluctuations on the critical point renormalization and demonstrate the existence of a two-photon pump “threshold”. It is noteworthy that the obtained results are in a good agreement with the numerical simulations.
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Affiliation(s)
- Valentin Yu. Mylnikov
- Ioffe Institute, 194021 St. Petersburg, Russia; (S.O.P.); (N.S.A.)
- Peter the Great St. Petersburg Polytechnic University, 195251 St. Petersburg, Russia
- Correspondence: (V.Y.M.); (G.S.S.)
| | | | - Grigorii S. Sokolovskii
- Ioffe Institute, 194021 St. Petersburg, Russia; (S.O.P.); (N.S.A.)
- Peter the Great St. Petersburg Polytechnic University, 195251 St. Petersburg, Russia
- Correspondence: (V.Y.M.); (G.S.S.)
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11
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Trade off-free entanglement stabilization in a superconducting qutrit-qubit system. Nat Commun 2022; 13:3994. [PMID: 35810169 PMCID: PMC9271051 DOI: 10.1038/s41467-022-31638-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 06/28/2022] [Indexed: 11/09/2022] Open
Abstract
Quantum reservoir engineering is a powerful framework for autonomous quantum state preparation and error correction. However, traditional approaches to reservoir engineering are hindered by unavoidable coherent leakage out of the target state, which imposes an inherent trade off between achievable steady-state state fidelity and stabilization rate. In this work we demonstrate a protocol that achieves trade off-free Bell state stabilization in a qutrit-qubit system realized on a circuit-QED platform. We accomplish this by creating a purely dissipative channel for population transfer into the target state, mediated by strong parametric interactions coupling the second-excited state of a superconducting transmon and the engineered bath resonator. Our scheme achieves a state preparation fidelity of 84% with a stabilization time constant of 339 ns, leading to a 54 ns error-time product in a solid-state quantum information platform.
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12
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Putterman H, Iverson J, Xu Q, Jiang L, Painter O, Brandão FGSL, Noh K. Stabilizing a Bosonic Qubit Using Colored Dissipation. PHYSICAL REVIEW LETTERS 2022; 128:110502. [PMID: 35363031 DOI: 10.1103/physrevlett.128.110502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 12/16/2021] [Accepted: 02/16/2022] [Indexed: 06/14/2023]
Abstract
Protected qubits such as the 0-π qubit, and bosonic qubits including cat qubits and Gottesman-Kitaev-Preskill (GKP) qubits offer advantages for fault tolerance. Some of these protected qubits (e.g., 0-π qubit and Kerr-cat qubit) are stabilized by Hamiltonians which have (near-)degenerate ground state manifolds with large energy gaps to the excited state manifolds. Without dissipative stabilization mechanisms the performance of such energy-gap-protected qubits can be limited by leakage to excited states. Here, we propose a scheme for dissipatively stabilizing an energy-gap-protected qubit using colored (i.e., frequency-selective) dissipation without inducing errors in the ground state manifold. Concretely we apply our colored dissipation technique to Kerr-cat qubits and propose colored Kerr-cat qubits which are protected by an engineered colored single-photon loss. When applied to the Kerr-cat qubits our scheme significantly suppresses leakage-induced bit-flip errors (which we show are a limiting error mechanism) while only using linear interactions. Beyond the benefits to the Kerr-cat qubit we also show that our frequency-selective loss technique can be applied to a broader class of protected qubits.
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Affiliation(s)
- Harald Putterman
- AWS Center for Quantum Computing, Pasadena, California 91125, USA
- IQIM, California Institute of Technology, Pasadena, California 91125, USA
| | - Joseph Iverson
- AWS Center for Quantum Computing, Pasadena, California 91125, USA
- IQIM, California Institute of Technology, Pasadena, California 91125, USA
| | - Qian Xu
- AWS Center for Quantum Computing, Pasadena, California 91125, USA
- Pritzker School of Molecular Engineering, The University of Chicago, Illinois 60637, USA
| | - Liang Jiang
- AWS Center for Quantum Computing, Pasadena, California 91125, USA
- Pritzker School of Molecular Engineering, The University of Chicago, Illinois 60637, USA
| | - Oskar Painter
- AWS Center for Quantum Computing, Pasadena, California 91125, USA
- IQIM, California Institute of Technology, Pasadena, California 91125, USA
| | - Fernando G S L Brandão
- AWS Center for Quantum Computing, Pasadena, California 91125, USA
- IQIM, California Institute of Technology, Pasadena, California 91125, USA
| | - Kyungjoo Noh
- AWS Center for Quantum Computing, Pasadena, California 91125, USA
- IQIM, California Institute of Technology, Pasadena, California 91125, USA
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13
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Triana JF, Arias M, Nishida J, Muller EA, Wilcken R, Johnson SC, Delgado A, Raschke MB, Herrera F. Semi-empirical Quantum Optics for Mid-Infrared Molecular Nanophotonics. J Chem Phys 2022; 156:124110. [DOI: 10.1063/5.0075894] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Nanoscale infrared (IR) resonators with sub-diffraction limited mode volumes and open geome- tries have emerged as new platforms for implementing cavity QED at room temperature. The use of infrared (IR) nano-antennas and tip nanoprobes to study strong light-matter coupling of molecular vibrations with the vacuum field can be exploited for IR quantum control with nanometer and femtosecond resolution. To accelerate the development of molecule-based quantum nano-photonic devices in the mid-IR, we propose a generally applicable semi-empirical methodology based on quantum optics to describe light-matter interaction in systems driven by femtosecond laser pulses. The theory is shown to reproduce recent experiments on the acceleration of the vibrational relaxation rate in infrared nanostructures, and also provide phys- ical insights for the implementation of coherent phase rotations of the near-field using broadband nanotips. We then apply the quantum framework to develop general tip-design rules for the exper- imental manipulation of vibrational strong coupling and Fano interference effects in open infrared resonators. We finally propose the possibility of transferring the natural anharmonicity of molecular vibrational levels to the resonator near-field in the weak coupling regime to implement intensity-dependent phase shifts of the coupled system response with strong pulses, and develop a vibrational chirping model to understand the effect. The semi-empirical quantum theory is equivalent to first- principles techniques based on Maxwell's equations, but its lower computational cost suggests its use a rapid design tool for the development of strongly-coupled infrared nanophotonic hardware for applications ranging from quantum control of materials to quantum information processing.
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Affiliation(s)
- Johan F Triana
- Region Metropolitana, Universidad de Santiago de Chile, Chile
| | | | - Jun Nishida
- University of Colorado Boulder, United States of America
| | - Eric A Muller
- Chemistry, Colgate University Division of Natural Sciences and Mathematics, United States of America
| | - Roland Wilcken
- University of Colorado at Boulder, United States of America
| | | | | | - Markus B. Raschke
- Department of Physics, University of Colorado at Boulder, United States of America
| | - Felipe Herrera
- Department of Physics, Universidad de Santiago de Chile, Chile
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14
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Gau M, Egger R, Zazunov A, Gefen Y. Driven Dissipative Majorana Dark Spaces. PHYSICAL REVIEW LETTERS 2020; 125:147701. [PMID: 33064546 DOI: 10.1103/physrevlett.125.147701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 09/01/2020] [Indexed: 06/11/2023]
Abstract
Pure quantum states can be stabilized in open quantum systems subject to external driving forces and dissipation by environmental modes. We show that driven dissipative (DD) Majorana devices offer key advantages for stabilizing degenerate state manifolds ("dark spaces") and for manipulating states in dark spaces, both with respect to native (non-DD) Majorana devices and to DD platforms with topologically trivial building blocks. For two tunnel-coupled Majorana boxes, using otherwise only standard hardware elements (e.g., a noisy electromagnetic environment and quantum dots with driven tunnel links), we propose a dark qubit encoding. We anticipate exceptionally high fault tolerance levels due to a conspiracy of DD-based autonomous error correction and topology.
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Affiliation(s)
- Matthias Gau
- Institut für Theoretische Physik, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany
- Department of Condensed Matter Physics, Weizmann Institute, Rehovot, Israel
| | - Reinhold Egger
- Institut für Theoretische Physik, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany
| | - Alex Zazunov
- Institut für Theoretische Physik, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany
| | - Yuval Gefen
- Department of Condensed Matter Physics, Weizmann Institute, Rehovot, Israel
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15
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Cian ZP, Zhu G, Chu SK, Seif A, DeGottardi W, Jiang L, Hafezi M. Photon Pair Condensation by Engineered Dissipation. PHYSICAL REVIEW LETTERS 2019; 123:063602. [PMID: 31491141 DOI: 10.1103/physrevlett.123.063602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Indexed: 06/10/2023]
Abstract
Dissipation can usually induce detrimental decoherence in a quantum system. However, engineered dissipation can be used to prepare and stabilize coherent quantum many-body states. Here, we show that, by engineering dissipators containing photon pair operators, one can stabilize an exotic dark state, which is a condensate of photon pairs with a phase-nematic order. In this system, the usual superfluid order parameter, i.e., single-photon correlation, is absent, while the photon pair correlation exhibits long-range order. Although the dark state is not unique due to multiple parity sectors, we devise an additional type of dissipators to stabilize the dark state in a particular parity sector via a diffusive annihilation process which obeys Glauber dynamics in an Ising model. Furthermore, we propose an implementation of these photon pair dissipators in circuit-QED architecture.
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Affiliation(s)
- Ze-Pei Cian
- Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
| | - Guanyu Zhu
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
| | - Su-Kuan Chu
- Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
- Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, Maryland 20742, USA
| | - Alireza Seif
- Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
| | - Wade DeGottardi
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
- Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742, USA
| | - Liang Jiang
- Departments of Applied Physics and Physics, Yale University, New Haven, Connecticut 06511, USA
- Yale Quantum Institute, Yale University, New Haven, Connecticut 06511, USA
| | - Mohammad Hafezi
- Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
- Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742, USA
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16
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Schiro M, Scarlatella O. Quantum impurity models coupled to Markovian and non-Markovian baths. J Chem Phys 2019; 151:044102. [PMID: 31370519 DOI: 10.1063/1.5100157] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We develop a method to study quantum impurity models, small interacting quantum systems bilinearly coupled to an environment, in the presence of an additional Markovian quantum bath, with a generic nonlinear coupling to the impurity. We aim at computing the evolution operator of the reduced density matrix of the impurity, obtained after tracing out all the environmental degrees of freedom. First, we derive an exact real-time hybridization expansion for this quantity, which generalizes the result obtained in the absence of the additional Markovian dissipation and which could be amenable to stochastic sampling through diagrammatic Monte Carlo. Then, we obtain a Dyson equation for this quantity and we evaluate its self-energy with a resummation technique known as the noncrossing approximation. We apply this novel approach to a simple fermionic impurity coupled to a zero temperature fermionic bath and in the presence of Markovian pump, losses, and dephasing.
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Affiliation(s)
- Marco Schiro
- JEIP, USR 3573 CNRS, Collége de France, PSL Research University, 11, place Marcelin Berthelot, 7 5231 Paris Cedex 05, France
| | - Orazio Scarlatella
- Institut de Physique Théorique, Université Paris Saclay, CNRS, CEA, F-91191 Gif-sur-Yvette, France
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17
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Li X, Xu Y, Zhao S. Quenching dissipative quantum Ising chain: an exact result for nonequilibrium dynamics. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:235402. [PMID: 30849768 DOI: 10.1088/1361-648x/ab0e47] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
To create a more comprehensive understanding of nonequilibrium dynamics of open quantum many-body systems, we visit an exactly solvable example, that is a quenched transverse-field Ising chain coupled to Markovian baths, which act locally on the Jordan-Wigner fermionic space. Performing explicit calculations on the heat transfer, transverse magnetization, and kink density, we find that the imbalance of two opposite damping mechanisms play a crucial role in constructing a nontrivial nonequilibrium steady state accompanied with a dissipative quantum phase transition, also that the competition between unitary drive and decoherence does not necessarily lead to a quasi-stationary state or prethermalization under certain ordinary relaxation.
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Affiliation(s)
- Xin Li
- Faculty of science, Kunming University of Science and Technology, Kunming 650093, People's Republic of China. State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, People's Republic of China
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18
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Lebreuilly J, Aron C, Mora C. Stabilizing Arrays of Photonic Cat States via Spontaneous Symmetry Breaking. PHYSICAL REVIEW LETTERS 2019; 122:120402. [PMID: 30978066 DOI: 10.1103/physrevlett.122.120402] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Indexed: 06/09/2023]
Abstract
The controlled generation and the protection of entanglement is key to quantum simulation and quantum computation. At the single-mode level, protocols based on photonic cat states hold strong promise as they present unprecedentedly long-lived coherence and may be combined with powerful error correction schemes. Here, we demonstrate that robust ensembles of "many-body photonic cat states" can be generated in a Bose-Hubbard model with pair hopping via a spontaneous U(1) symmetry-breaking mechanism. We identify a parameter region where the ground state is a massively degenerate manifold consisting of local cat states which are factorized throughout the lattice and whose conserved individual parities can be used to make a register of qubits. This phenomenology occurs for arbitrary system sizes or geometries, as soon as long-range order is established, and it extends to driven-dissipative conditions. In the thermodynamic limit, it is related to a Mott insulator to pair-superfluid phase transition.
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Affiliation(s)
- José Lebreuilly
- Laboratoire Pierre Aigrain, École Normale Supérieure-PSL Research University, CNRS, Université Pierre et Marie Curie-Sorbonne Université, Université Paris Diderot-Sorbonne Paris Cité, Paris 75005, France
| | - Camille Aron
- Laboratoire de Physique Théorique, École Normale Supérieure, CNRS, PSL University, Sorbonne Université, Paris 75005, France
- Instituut voor Theoretische Fysica, KU Leuven 3001, Belgium
| | - Christophe Mora
- Laboratoire Pierre Aigrain, École Normale Supérieure-PSL Research University, CNRS, Université Pierre et Marie Curie-Sorbonne Université, Université Paris Diderot-Sorbonne Paris Cité, Paris 75005, France
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19
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Gely MF, Kounalakis M, Dickel C, Dalle J, Vatré R, Baker B, Jenkins MD, Steele GA. Observation and stabilization of photonic Fock states in a hot radio-frequency resonator. Science 2019; 363:1072-1075. [DOI: 10.1126/science.aaw3101] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 02/07/2019] [Indexed: 11/02/2022]
Affiliation(s)
- Mario F. Gely
- Kavli Institute of NanoScience, Delft University of Technology, Post Office Box 5046, 2600 GA, Delft, Netherlands
| | - Marios Kounalakis
- Kavli Institute of NanoScience, Delft University of Technology, Post Office Box 5046, 2600 GA, Delft, Netherlands
| | - Christian Dickel
- Kavli Institute of NanoScience, Delft University of Technology, Post Office Box 5046, 2600 GA, Delft, Netherlands
| | - Jacob Dalle
- Kavli Institute of NanoScience, Delft University of Technology, Post Office Box 5046, 2600 GA, Delft, Netherlands
| | - Rémy Vatré
- Kavli Institute of NanoScience, Delft University of Technology, Post Office Box 5046, 2600 GA, Delft, Netherlands
| | - Brian Baker
- Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208, USA
| | - Mark D. Jenkins
- Kavli Institute of NanoScience, Delft University of Technology, Post Office Box 5046, 2600 GA, Delft, Netherlands
| | - Gary A. Steele
- Kavli Institute of NanoScience, Delft University of Technology, Post Office Box 5046, 2600 GA, Delft, Netherlands
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20
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Elouard C, Besga B, Auffèves A. Probing the State of a Mechanical Oscillator with an Ultrastrongly Coupled Quantum Emitter. PHYSICAL REVIEW LETTERS 2019; 122:013602. [PMID: 31012721 DOI: 10.1103/physrevlett.122.013602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Indexed: 06/09/2023]
Abstract
Performing accurate position measurements of a mechanical resonator by coupling it to some optically driven quantum emitter is an important challenge for quantum sensing and metrology. We fully characterize the quantum noise associated with this measurement process, by deriving master equations for the coupled emitter and the resonator valid in the ultrastrong coupling regime. At short timescales, we show that this noise sets a fundamental limit to the readout sensitivity and that the standard quantum limit can be recovered for realistic experimental conditions. At long timescales, the scattering of the mechanical quadratures leads to the decoupling of the emitter from the driving light, switching off the noise source. This method can be used to describe the interaction of any quantum system strongly coupled to a finite size reservoir.
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Affiliation(s)
- Cyril Elouard
- Department of Physics and Astronomy and Center for Coherence and Quantum Optics, University of Rochester, Rochester, New York 14627, USA
| | - Benjamin Besga
- Université de Lyon, CNRS, Laboratoire de Physique de l'École Normale Supérieure, UMR5672, 46 Allée d'Italie, 69364 Lyon, France
| | - Alexia Auffèves
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France
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21
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Magnard P, Kurpiers P, Royer B, Walter T, Besse JC, Gasparinetti S, Pechal M, Heinsoo J, Storz S, Blais A, Wallraff A. Fast and Unconditional All-Microwave Reset of a Superconducting Qubit. PHYSICAL REVIEW LETTERS 2018; 121:060502. [PMID: 30141638 DOI: 10.1103/physrevlett.121.060502] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Indexed: 06/08/2023]
Abstract
Active qubit reset is a key operation in many quantum algorithms, and particularly in quantum error correction. Here, we experimentally demonstrate a reset scheme for a three-level transmon artificial atom coupled to a large bandwidth resonator. The reset protocol uses a microwave-induced interaction between the |f,0⟩ and |g,1⟩ states of the coupled transmon-resonator system, with |g⟩ and |f⟩ denoting the ground and second excited states of the transmon, and |0⟩ and |1⟩ the photon Fock states of the resonator. We characterize the reset process and demonstrate reinitialization of the transmon-resonator system to its ground state in less than 500 ns and with 0.2% residual excitation. Our protocol is of practical interest as it has no additional architectural requirements beyond those needed for fast and efficient single-shot readout of transmons, and does not require feedback.
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Affiliation(s)
- P Magnard
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - P Kurpiers
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - B Royer
- Institut Quantique and Département de Physique, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
| | - T Walter
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - J-C Besse
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - S Gasparinetti
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - M Pechal
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - J Heinsoo
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - S Storz
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - A Blais
- Institut Quantique and Département de Physique, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
- Canadian Institute for Advanced Research, Toronto, Ontario M5G IZ8, Canada
| | - A Wallraff
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
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22
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Hou QZ, You JB, Yang WL, An JH, Chen CY, Feng M. Generation of multiqubit steady-state quantum correlation by squeezed-reservoir engineering. OPTICS EXPRESS 2018; 26:20459-20470. [PMID: 30119356 DOI: 10.1364/oe.26.020459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 07/08/2018] [Indexed: 06/08/2023]
Abstract
Stationary quantum correlation among two-level systems (TLSs) in steady state is one of unique resources for applications in quantum information processing. Here we propose a scheme to generate such quantum correlation among the TLSs inside a lossy cavity. It is found that, by applying a broadband squeezed laser acting as a squeezed-vacuum reservoir to the cavity, a stable quantum correlation of the TLSs can be generated. By adiabatically eliminating the cavity field, we derive a reduced master equation of the TLSs in the bad-cavity limit. We show that the generated quantum correlation is essentially determined by the squeezing features transferred from the squeezed-vacuum reservoir via the cavity field as a quantum bus. We study the effect of the system parameters, such as the squeezing, the detuning, the coupling strength, and the decay rate of the TLSs, on the performance of the scheme. The feasibility of our proposal is supported by the application of currently available experimental techniques.
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23
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Yan F, Campbell D, Krantz P, Kjaergaard M, Kim D, Yoder JL, Hover D, Sears A, Kerman AJ, Orlando TP, Gustavsson S, Oliver WD. Distinguishing Coherent and Thermal Photon Noise in a Circuit Quantum Electrodynamical System. PHYSICAL REVIEW LETTERS 2018; 120:260504. [PMID: 30004727 DOI: 10.1103/physrevlett.120.260504] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Indexed: 06/08/2023]
Abstract
In the cavity-QED architecture, photon number fluctuations from residual cavity photons cause qubit dephasing due to the ac Stark effect. These unwanted photons originate from a variety of sources, such as thermal radiation, leftover measurement photons, and cross talk. Using a capacitively shunted flux qubit coupled to a transmission line cavity, we demonstrate a method that identifies and distinguishes coherent and thermal photons based on noise-spectral reconstruction from time-domain spin-locking relaxometry. Using these measurements, we attribute the limiting dephasing source in our system to thermal photons rather than coherent photons. By improving the cryogenic attenuation on lines leading to the cavity, we successfully suppress residual thermal photons and achieve T_{1}-limited spin-echo decay time. The spin-locking noise-spectroscopy technique allows broad frequency access and readily applies to other qubit modalities for identifying general asymmetric nonclassical noise spectra.
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Affiliation(s)
- Fei Yan
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Dan Campbell
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Philip Krantz
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Morten Kjaergaard
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - David Kim
- MIT Lincoln Laboratory, 244 Wood Street, Lexington, Massachusetts 02420, USA
| | - Jonilyn L Yoder
- MIT Lincoln Laboratory, 244 Wood Street, Lexington, Massachusetts 02420, USA
| | - David Hover
- MIT Lincoln Laboratory, 244 Wood Street, Lexington, Massachusetts 02420, USA
| | - Adam Sears
- MIT Lincoln Laboratory, 244 Wood Street, Lexington, Massachusetts 02420, USA
| | - Andrew J Kerman
- MIT Lincoln Laboratory, 244 Wood Street, Lexington, Massachusetts 02420, USA
| | - Terry P Orlando
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Simon Gustavsson
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - William D Oliver
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- MIT Lincoln Laboratory, 244 Wood Street, Lexington, Massachusetts 02420, USA
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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24
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Enhancing Metastability by Dissipation and Driving in an Asymmetric Bistable Quantum System. ENTROPY 2018; 20:e20040226. [PMID: 33265317 PMCID: PMC7512741 DOI: 10.3390/e20040226] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 03/01/2018] [Accepted: 03/23/2018] [Indexed: 12/19/2022]
Abstract
The stabilizing effect of quantum fluctuations on the escape process and the relaxation dynamics from a quantum metastable state are investigated. Specifically, the quantum dynamics of a multilevel bistable system coupled to a bosonic Ohmic thermal bath in strong dissipation regime is analyzed. The study is performed by a non-perturbative method based on the real-time path integral approach of the Feynman-Vernon influence functional. We consider a strongly asymmetric double well potential with and without a monochromatic external driving, and with an out-of-equilibrium initial condition. In the absence of driving we observe a nonmonotonic behavior of the escape time from the metastable region, as a function both of the system-bath coupling coefficient and the temperature. This indicates a stabilizing effect of the quantum fluctuations. In the presence of driving our findings indicate that, as the coupling coefficient γ increases, the escape time, initially controlled by the external driving, shows resonant peaks and dips, becoming frequency-independent for higher γ values. Moreover, the escape time from the metastable state displays a nonmonotonic behavior as a function of the temperature, the frequency of the driving, and the thermal-bath coupling, which indicates the presence of a quantum noise enhanced stability phenomenon. Finally, we investigate the role of different spectral densities, both in sub-Ohmic and super-Ohmic dissipation regime and for different cutoff frequencies, on the relaxation dynamics from the quantum metastable state. The results obtained indicate that, in the crossover dynamical regime characterized by damped intrawell oscillations and incoherent tunneling, the spectral properties of the thermal bath influence non-trivially the short time behavior and the time scales of the relaxation dynamics from the metastable state.
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25
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Lu Y, Chakram S, Leung N, Earnest N, Naik RK, Huang Z, Groszkowski P, Kapit E, Koch J, Schuster DI. Universal Stabilization of a Parametrically Coupled Qubit. PHYSICAL REVIEW LETTERS 2017; 119:150502. [PMID: 29077454 DOI: 10.1103/physrevlett.119.150502] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Indexed: 06/07/2023]
Abstract
We autonomously stabilize arbitrary states of a qubit through parametric modulation of the coupling between a fixed frequency qubit and resonator. The coupling modulation is achieved with a tunable coupling design, in which the qubit and the resonator are connected in parallel to a superconducting quantum interference device. This allows for quasistatic tuning of the qubit-cavity coupling strength from 12 MHz to more than 300 MHz. Additionally, the coupling can be dynamically modulated, allowing for single-photon exchange in 6 ns. Qubit coherence times exceeding 20 μs are maintained over the majority of the range of tuning, limited primarily by the Purcell effect. The parametric stabilization technique realized using the tunable coupler involves engineering the qubit bath through a combination of photon nonconserving sideband interactions realized by flux modulation, and direct qubit Rabi driving. We demonstrate that the qubit can be stabilized to arbitrary states on the Bloch sphere with a worst-case fidelity exceeding 80%.
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Affiliation(s)
- Yao Lu
- The James Franck Institute and Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - S Chakram
- The James Franck Institute and Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - N Leung
- The James Franck Institute and Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - N Earnest
- The James Franck Institute and Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - R K Naik
- The James Franck Institute and Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - Ziwen Huang
- Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA
| | - Peter Groszkowski
- Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA
| | - Eliot Kapit
- Department of Physics and Engineering Physics, Tulane University, New Orleans, Louisiana 70118, USA
| | - Jens Koch
- Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA
| | - David I Schuster
- The James Franck Institute and Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
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26
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Éthier-Majcher G, Gangloff D, Stockill R, Clarke E, Hugues M, Le Gall C, Atatüre M. Improving a Solid-State Qubit through an Engineered Mesoscopic Environment. PHYSICAL REVIEW LETTERS 2017; 119:130503. [PMID: 29341723 DOI: 10.1103/physrevlett.119.130503] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Indexed: 06/07/2023]
Abstract
A controlled quantum system can alter its environment by feedback, leading to reduced-entropy states of the environment and to improved system coherence. Here, using a quantum-dot electron spin as a control and probe, we prepare the quantum-dot nuclei under the feedback of coherent population trapping and observe their evolution from a thermal to a reduced-entropy state, with the immediate consequence of extended qubit coherence. Via Ramsey interferometry on the electron spin, we directly access the nuclear distribution following its preparation and measure the emergence and decay of correlations within the nuclear ensemble. Under optimal feedback, the inhomogeneous dephasing time of the electron, T_{2}^{*}, is extended by an order of magnitude to 39 ns. Our results can be readily exploited in quantum information protocols utilizing spin-photon entanglement and represent a step towards creating quantum many-body states in a mesoscopic nuclear-spin ensemble.
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Affiliation(s)
- G Éthier-Majcher
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - D Gangloff
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - R Stockill
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - E Clarke
- EPSRC National Centre for III-V Technologies, University of Sheffield, Sheffield S1 3JD, United Kingdom
| | - M Hugues
- Université Côte d'Azur, CNRS, CRHEA, rue Bernard Gregory, 06560 Valbonne, France
| | - C Le Gall
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - M Atatüre
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
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27
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Hacohen-Gourgy S, Martin LS, Flurin E, Ramasesh VV, Whaley KB, Siddiqi I. Quantum dynamics of simultaneously measured non-commuting observables. Nature 2016; 538:491-494. [DOI: 10.1038/nature19762] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/02/2016] [Indexed: 11/09/2022]
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28
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Vool U, Shankar S, Mundhada SO, Ofek N, Narla A, Sliwa K, Zalys-Geller E, Liu Y, Frunzio L, Schoelkopf RJ, Girvin SM, Devoret MH. Continuous Quantum Nondemolition Measurement of the Transverse Component of a Qubit. PHYSICAL REVIEW LETTERS 2016; 117:133601. [PMID: 27715126 DOI: 10.1103/physrevlett.117.133601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Indexed: 06/06/2023]
Abstract
Quantum jumps of a qubit are usually observed between its energy eigenstates, also known as its longitudinal pseudospin component. Is it possible, instead, to observe quantum jumps between the transverse superpositions of these eigenstates? We answer positively by presenting the first continuous quantum nondemolition measurement of the transverse component of an individual qubit. In a circuit QED system irradiated by two pump tones, we engineer an effective Hamiltonian whose eigenstates are the transverse qubit states, and a dispersive measurement of the corresponding operator. Such transverse component measurements are a useful tool in the driven-dissipative operation engineering toolbox, which is central to quantum simulation and quantum error correction.
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Affiliation(s)
- U Vool
- 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
| | - S O Mundhada
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - N Ofek
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - A Narla
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - K Sliwa
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - E Zalys-Geller
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Y Liu
- 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
| | - R J Schoelkopf
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - S M Girvin
- 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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29
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Kimchi-Schwartz ME, Martin L, Flurin E, Aron C, Kulkarni M, Tureci HE, Siddiqi I. Stabilizing Entanglement via Symmetry-Selective Bath Engineering in Superconducting Qubits. PHYSICAL REVIEW LETTERS 2016; 116:240503. [PMID: 27367372 DOI: 10.1103/physrevlett.116.240503] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Indexed: 06/06/2023]
Abstract
Bath engineering, which utilizes coupling to lossy modes in a quantum system to generate nontrivial steady states, is a tantalizing alternative to gate- and measurement-based quantum science. Here, we demonstrate dissipative stabilization of entanglement between two superconducting transmon qubits in a symmetry-selective manner. We utilize the engineered symmetries of the dissipative environment to stabilize a target Bell state; we further demonstrate suppression of the Bell state of opposite symmetry due to parity selection rules. This implementation is resource efficient, achieves a steady-state fidelity F=0.70, and is scalable to multiple qubits.
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Affiliation(s)
- M E Kimchi-Schwartz
- Quantum Nanoelectronics Laboratory, Department of Physics, University of California, Berkeley, California 94720, USA
| | - L Martin
- Quantum Nanoelectronics Laboratory, Department of Physics, University of California, Berkeley, California 94720, USA
| | - E Flurin
- Quantum Nanoelectronics Laboratory, Department of Physics, University of California, Berkeley, California 94720, USA
| | - C Aron
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
- Laboratoire de Physique Théorique, École Normale Supérieure, CNRS, Paris, France
- Instituut voor Theoretische Fysica, KU Leuven, Belgium
| | - M Kulkarni
- Department of Physics, New York City College of Technology, The City University of New York, Brooklyn, New York 11201, USA
| | - H E Tureci
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - I Siddiqi
- Quantum Nanoelectronics Laboratory, Department of Physics, University of California, Berkeley, California 94720, USA
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30
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Puri S, Blais A. High-Fidelity Resonator-Induced Phase Gate with Single-Mode Squeezing. PHYSICAL REVIEW LETTERS 2016; 116:180501. [PMID: 27203311 DOI: 10.1103/physrevlett.116.180501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Indexed: 06/05/2023]
Abstract
We propose to increase the fidelity of two-qubit resonator-induced phase gates in circuit QED by the use of narrow-band single-mode squeezing. We show that there exists an optimal squeezing angle and strength that erases qubit "which-path" information leaking out of the cavity and thereby minimizes qubit dephasing during these gates. Our analytical results for the gate fidelity are in excellent agreement with numerical simulations of a cascaded master equation that takes into account the dynamics of the source of squeezed radiation. With realistic parameters, we find that it is possible to realize a controlled-phase gate with a gate time of 200 ns and average infidelity of 10^{-5}.
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Affiliation(s)
- Shruti Puri
- Départment de Physique, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K 2R1
| | - Alexandre Blais
- Départment de Physique, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K 2R1
- Canadian Institute for Advanced Research, Toronto, Canada
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31
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Kapit E. Hardware-Efficient and Fully Autonomous Quantum Error Correction in Superconducting Circuits. PHYSICAL REVIEW LETTERS 2016; 116:150501. [PMID: 27127945 DOI: 10.1103/physrevlett.116.150501] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Indexed: 06/05/2023]
Abstract
Superconducting qubits are among the most promising platforms for building a quantum computer. However, individual qubit coherence times are not far past the scalability threshold for quantum error correction, meaning that millions of physical devices would be required to construct a useful quantum computer. Consequently, further increases in coherence time are very desirable. In this Letter, we blueprint a simple circuit consisting of two transmon qubits and two additional lossy qubits or resonators, which is passively protected against all single-qubit quantum error channels through a combination of continuous driving and engineered dissipation. Photon losses are rapidly corrected through two-photon drive fields implemented with driven superconducting quantum interference device couplings, and dephasing from random potential fluctuations is heavily suppressed by the drive fields used to implement the multiqubit Hamiltonian. Comparing our theoretical model to published noise estimates from recent experiments on flux and transmon qubits, we find that logical state coherence could be improved by a factor of 40 or more compared to the individual qubit T_{1} and T_{2} using this technique. We thus demonstrate that there is substantial headroom for improving the coherence of modern superconducting qubits with a fairly modest increase in device complexity.
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Affiliation(s)
- Eliot Kapit
- Department of Physics and Engineering Physics, Tulane University, New Orleans, Louisiana 70118, USA and Initiative for Theoretical Science, The Graduate Center, City University of New York, New York, New York 10016, USA
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32
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Alonso JJ, Lutz E, Romito A. Thermodynamics of Weakly Measured Quantum Systems. PHYSICAL REVIEW LETTERS 2016; 116:080403. [PMID: 26967399 DOI: 10.1103/physrevlett.116.080403] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Indexed: 06/05/2023]
Abstract
We consider continuously monitored quantum systems and introduce definitions of work and heat along individual quantum trajectories that are valid for coherent superposition of energy eigenstates. We use these quantities to extend the first and second laws of stochastic thermodynamics to the quantum domain. We illustrate our results with the case of a weakly measured driven two-level system and show how to distinguish between quantum work and heat contributions. We finally employ quantum feedback control to suppress detector backaction and determine the work statistics.
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Affiliation(s)
- Jose Joaquin Alonso
- Department of Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, D-91058 Erlangen, Germany
| | - Eric Lutz
- Department of Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, D-91058 Erlangen, Germany
| | - Alessandro Romito
- Dahlem Center for Complex Quantum Systems, FU Berlin, D-14195 Berlin, Germany
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33
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Hacohen-Gourgy S, Ramasesh VV, De Grandi C, Siddiqi I, Girvin SM. Cooling and Autonomous Feedback in a Bose-Hubbard Chain with Attractive Interactions. PHYSICAL REVIEW LETTERS 2015; 115:240501. [PMID: 26705615 DOI: 10.1103/physrevlett.115.240501] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Indexed: 06/05/2023]
Abstract
We engineer a quantum bath that enables entropy and energy exchange with a one-dimensional Bose-Hubbard lattice with attractive on-site interactions. We implement this in an array of three superconducting transmon qubits coupled to a single cavity mode; the transmons represent lattice sites and their excitation quanta embody bosonic particles. Our cooling protocol preserves the particle number-realizing a canonical ensemble-and also affords the efficient preparation of dark states which, due to symmetry, cannot be prepared via coherent drives on the cavity. Furthermore, by applying continuous microwave radiation, we also realize autonomous feedback to indefinitely stabilize particular eigenstates of the array.
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Affiliation(s)
- S Hacohen-Gourgy
- Quantum Nanoelectronics Laboratory, Department of Physics, University of California, Berkeley, California 94720, USA
| | - V V Ramasesh
- Quantum Nanoelectronics Laboratory, Department of Physics, University of California, Berkeley, California 94720, USA
| | - C De Grandi
- Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - I Siddiqi
- Quantum Nanoelectronics Laboratory, Department of Physics, University of California, Berkeley, California 94720, USA
| | - S M Girvin
- Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520, USA
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34
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Holland ET, Vlastakis B, Heeres RW, Reagor MJ, Vool U, Leghtas Z, Frunzio L, Kirchmair G, Devoret MH, Mirrahimi M, Schoelkopf RJ. Single-Photon-Resolved Cross-Kerr Interaction for Autonomous Stabilization of Photon-Number States. PHYSICAL REVIEW LETTERS 2015; 115:180501. [PMID: 26565448 DOI: 10.1103/physrevlett.115.180501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Indexed: 06/05/2023]
Abstract
Quantum states can be stabilized in the presence of intrinsic and environmental losses by either applying an active feedback condition on an ancillary system or through reservoir engineering. Reservoir engineering maintains a desired quantum state through a combination of drives and designed entropy evacuation. We propose and implement a quantum-reservoir engineering protocol that stabilizes Fock states in a microwave cavity. This protocol is realized with a circuit quantum electrodynamics platform where a Josephson junction provides direct, nonlinear coupling between two superconducting waveguide cavities. The nonlinear coupling results in a single-photon-resolved cross-Kerr effect between the two cavities enabling a photon-number-dependent coupling to a lossy environment. The quantum state of the microwave cavity is discussed in terms of a net polarization and is analyzed by a measurement of its steady state Wigner function.
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Affiliation(s)
- E T Holland
- Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - B Vlastakis
- Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - R W Heeres
- Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - M J Reagor
- Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - U Vool
- Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Z Leghtas
- Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - L Frunzio
- Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - G Kirchmair
- Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520, USA
- Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck, Austria
- Institute for Experimental Physics, University of Innsbruck, A-6020 Innsbruck, Austria
| | - M H Devoret
- Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - M Mirrahimi
- Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520, USA
- INRIA Paris-Rocquencourt, Domaine de Voluceau, B.P. 105, 78153 Le Chesnay Cedex, France
| | - R J Schoelkopf
- Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520, USA
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35
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Leghtas Z, Touzard S, Pop IM, Kou A, Vlastakis B, Petrenko A, Sliwa KM, Narla A, Shankar S, Hatridge MJ, Reagor M, Frunzio L, Schoelkopf RJ, Mirrahimi M, Devoret MH. Confining the state of light to a quantum manifold by engineered two-photon loss. Science 2015; 347:853-7. [DOI: 10.1126/science.aaa2085] [Citation(s) in RCA: 262] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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36
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Souquet JR, Woolley MJ, Gabelli J, Simon P, Clerk AA. Photon-assisted tunnelling with nonclassical light. Nat Commun 2014; 5:5562. [PMID: 25424422 PMCID: PMC4263132 DOI: 10.1038/ncomms6562] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Accepted: 10/14/2014] [Indexed: 11/23/2022] Open
Abstract
Among the most exciting recent advances in the field of superconducting quantum circuits is the ability to coherently couple microwave photons in low-loss cavities to quantum electronic conductors. These hybrid quantum systems hold great promise for quantum information-processing applications; even more strikingly, they enable exploration of new physical regimes. Here we study theoretically the new physics emerging when a quantum electronic conductor is exposed to nonclassical microwaves (for example, squeezed states, Fock states). We study this interplay in the experimentally relevant situation where a superconducting microwave cavity is coupled to a conductor in the tunnelling regime. We find that the conductor acts as a nontrivial probe of the microwave state: the emission and absorption of photons by the conductor is characterized by a nonpositive definite quasi-probability distribution, which is related to the Glauber–Sudarshan P-function of quantum optics. These negative quasi-probabilities have a direct influence on the conductance of the conductor. Coherently coupling microwave photons to quantum electronic conductors could provide a useful platform for quantum information processing. Souquet et al. now theoretically demonstrate that such systems can also act as sensitive probes of the quantum properties of non-classical microwave radiation.
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Affiliation(s)
- J-R Souquet
- 1] Laboratoire de Physique des Solides, Université Paris-Sud, Orsay 91405, France [2] Department of Physics, McGill University, Montréal, Quebec, Canada
| | - M J Woolley
- School of Engineering and Information Technology, University of New South Wales, ADFA, Canberra, Australian Capital Territory 2600, Australia
| | - J Gabelli
- Laboratoire de Physique des Solides, Université Paris-Sud, Orsay 91405, France
| | - P Simon
- Laboratoire de Physique des Solides, Université Paris-Sud, Orsay 91405, France
| | - A A Clerk
- Department of Physics, McGill University, Montréal, Quebec, Canada
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37
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Navarrete-Benlloch C, García-Ripoll JJ, Porras D. Inducing nonclassical lasing via periodic drivings in circuit quantum electrodynamics. PHYSICAL REVIEW LETTERS 2014; 113:193601. [PMID: 25415906 DOI: 10.1103/physrevlett.113.193601] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Indexed: 06/04/2023]
Abstract
We show how a pair of superconducting qubits coupled to a microwave cavity mode can be used to engineer a single-atom laser that emits light into a nonclassical state. Our scheme relies on the dressing of the qubit-field coupling by periodic modulations of the qubit energy. In the dressed basis, the radiative decay of the first qubit becomes an effective incoherent pumping mechanism that injects energy into the system, hence turning dissipation to our advantage. A second, auxiliary qubit is used to shape the decay within the cavity, in such a way that lasing occurs in a squeezed basis of the cavity mode. We characterize the system both by mean-field theory and exact calculations. Our work may find applications in the generation of squeezing and entanglement in circuit QED, as well as in the study of dissipative few- and many-body phase transitions.
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Affiliation(s)
| | | | - Diego Porras
- Department of Physics and Astronomy, University of Sussex, Falmer, Brighton BN19QH, United Kingdom and Departamento de Física Teórica I, Universidad Complutense, 28040 Madrid, Spain
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38
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Yang CJ, An JH, Luo HG, Li Y, Oh CH. Canonical versus noncanonical equilibration dynamics of open quantum systems. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 90:022122. [PMID: 25215704 DOI: 10.1103/physreve.90.022122] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Indexed: 06/03/2023]
Abstract
In statistical mechanics, any quantum system in equilibrium with its weakly coupled reservoir is described by a canonical state at the same temperature as the reservoir. Here, by studying the equilibration dynamics of a harmonic oscillator interacting with a reservoir, we evaluate microscopically the condition under which the equilibration to a canonical state is valid. It is revealed that the non-Markovian effect and the availability of a stationary state of the total system play a profound role in the equilibration. In the Markovian limit, the conventional canonical state can be recovered. In the non-Markovian regime, when the stationary state is absent, the system equilibrates to a generalized canonical state at an effective temperature; whenever the stationary state is present, the equilibrium state of the system cannot be described by any canonical state anymore. Our finding of the physical condition on such noncanonical equilibration might have significant impact on statistical physics. A physical scheme based on circuit QED is proposed to test our results.
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Affiliation(s)
- Chun-Jie Yang
- Center for Interdisciplinary Studies, School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China and Qian Xuesen Laboratory of Space Technology, China Academy of Space Technology in China Aerospace Science and Technology Corporation, Beijing 100094, China
| | - Jun-Hong An
- Center for Interdisciplinary Studies, School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China and Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore
| | - Hong-Gang Luo
- Center for Interdisciplinary Studies, School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China and Beijing Computational Science Research Center, Beijing 100084, China
| | - Yading Li
- Qian Xuesen Laboratory of Space Technology, China Academy of Space Technology in China Aerospace Science and Technology Corporation, Beijing 100094, China
| | - C H Oh
- Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore
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39
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Gramich V, Gasparinetti S, Solinas P, Ankerhold J. Lamb-shift enhancement and detection in strongly driven superconducting circuits. PHYSICAL REVIEW LETTERS 2014; 113:027001. [PMID: 25062221 DOI: 10.1103/physrevlett.113.027001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Indexed: 06/03/2023]
Abstract
It is shown that strong driving of a quantum system substantially enhances the Lamb shift induced by broadband reservoirs, which are typical for solid-state devices. By varying drive parameters the impact of environmental vacuum fluctuations with continuous spectral distribution onto system observables can be tuned in a distinctive way. This provides experimentally feasible measurement schemes for the Lamb shift in superconducting circuits based on Cooper pair boxes, where it can be detected either in shifted dressed transition frequencies or in pumped charge currents.
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Affiliation(s)
- Vera Gramich
- Institut für Theoretische Physik, Universität Ulm, Albert-Einstein-Allee 11, 89069 Ulm, Germany and Low Temperature Laboratory (OVLL), Aalto University School of Science, P.O. Box 13500, 00076 Aalto, Finland
| | - Simone Gasparinetti
- Low Temperature Laboratory (OVLL), Aalto University School of Science, P.O. Box 13500, 00076 Aalto, Finland
| | - Paolo Solinas
- Low Temperature Laboratory (OVLL), Aalto University School of Science, P.O. Box 13500, 00076 Aalto, Finland and SPIN-CNR, Via Dodecaneso 33, 16146 Genova, Italy
| | - Joachim Ankerhold
- Institut für Theoretische Physik, Universität Ulm, Albert-Einstein-Allee 11, 89069 Ulm, Germany
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40
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Szigeti SS, Carvalho ARR, Morley JG, Hush MR. Ignorance is bliss: general and robust cancellation of decoherence via no-knowledge quantum feedback. PHYSICAL REVIEW LETTERS 2014; 113:020407. [PMID: 25062148 DOI: 10.1103/physrevlett.113.020407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Indexed: 06/03/2023]
Abstract
A "no-knowledge" measurement of an open quantum system yields no information about any system observable; it only returns noise input from the environment. Surprisingly, performing such a no-knowledge measurement can be advantageous. We prove that a system undergoing no-knowledge monitoring has reversible noise, which can be canceled by directly feeding back the measurement signal. We show how no-knowledge feedback control can be used to cancel decoherence in an arbitrary quantum system coupled to a Markovian reservoir that is being monitored. Since no-knowledge feedback does not depend on the system state or Hamiltonian, such decoherence cancellation is guaranteed to be general and robust, and can operate in conjunction with any other quantum control protocol. As an application, we show that no-knowledge feedback could be used to improve the performance of dissipative quantum computers subjected to local loss.
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Affiliation(s)
| | - Andre R R Carvalho
- Department of Quantum Science, Research School of Physics and Engineering, The Australian National University, Canberra, Australian Capital Territory 0200, Australia and ARC Centre for Quantum Computation and Communication Technology, The Australian National University, Canberra, Australian Capital Territory 0200, Australia
| | - James G Morley
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Michael R Hush
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
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41
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Wood CJ, Borneman TW, Cory DG. Cavity cooling of an ensemble spin system. PHYSICAL REVIEW LETTERS 2014; 112:050501. [PMID: 24580576 DOI: 10.1103/physrevlett.112.050501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Indexed: 06/03/2023]
Abstract
We describe how sideband cooling techniques may be applied to large spin ensembles in magnetic resonance. Using the Tavis-Cummings model in the presence of a Rabi drive, we solve a Markovian master equation describing the joint spin-cavity dynamics to derive cooling rates as a function of ensemble size. Our calculations indicate that the coupled angular momentum subspaces of a spin ensemble containing roughly 10(11) electron spins may be polarized in a time many orders of magnitude shorter than the typical thermal relaxation time. The described techniques should permit efficient removal of entropy for spin-based quantum information processors and fast polarization of spin samples. The proposed application of a standard technique in quantum optics to magnetic resonance also serves to reinforce the connection between the two fields, which has recently begun to be explored in further detail due to the development of hybrid designs for manufacturing noise-resilient quantum devices.
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Affiliation(s)
- Christopher J Wood
- Institute for Quantum Computing, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada and Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Troy W Borneman
- Institute for Quantum Computing, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada and Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - David G Cory
- Institute for Quantum Computing, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada and Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada and Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5, Canada
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42
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Roßnagel J, Abah O, Schmidt-Kaler F, Singer K, Lutz E. Nanoscale heat engine beyond the Carnot limit. PHYSICAL REVIEW LETTERS 2014; 112:030602. [PMID: 24484127 DOI: 10.1103/physrevlett.112.030602] [Citation(s) in RCA: 195] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Indexed: 06/03/2023]
Abstract
We consider a quantum Otto cycle for a time-dependent harmonic oscillator coupled to a squeezed thermal reservoir. We show that the efficiency at maximum power increases with the degree of squeezing, surpassing the standard Carnot limit and approaching unity exponentially for large squeezing parameters. We further propose an experimental scheme to implement such a model system by using a single trapped ion in a linear Paul trap with special geometry. Our analytical investigations are supported by Monte Carlo simulations that demonstrate the feasibility of our proposal. For realistic trap parameters, an increase of the efficiency at maximum power of up to a factor of 4 is reached, largely exceeding the Carnot bound.
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Affiliation(s)
- J Roßnagel
- Quantum, Institut für Physik, Universität Mainz, D-55128 Mainz, Germany
| | - O Abah
- Institute for Theoretical Physics, University of Erlangen-Nürnberg, D-91058 Erlangen, Germany
| | - F Schmidt-Kaler
- Quantum, Institut für Physik, Universität Mainz, D-55128 Mainz, Germany
| | - K Singer
- Quantum, Institut für Physik, Universität Mainz, D-55128 Mainz, Germany
| | - E Lutz
- Institute for Theoretical Physics, University of Erlangen-Nürnberg, D-91058 Erlangen, Germany
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43
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Shankar S, Hatridge M, Leghtas Z, Sliwa KM, Narla A, Vool U, Girvin SM, Frunzio L, Mirrahimi M, Devoret MH. Autonomously stabilized entanglement between two superconducting quantum bits. Nature 2013; 504:419-22. [PMID: 24270808 DOI: 10.1038/nature12802] [Citation(s) in RCA: 234] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 10/22/2013] [Indexed: 12/27/2022]
Abstract
Quantum error correction codes are designed to protect an arbitrary state of a multi-qubit register from decoherence-induced errors, but their implementation is an outstanding challenge in the development of large-scale quantum computers. The first step is to stabilize a non-equilibrium state of a simple quantum system, such as a quantum bit (qubit) or a cavity mode, in the presence of decoherence. This has recently been accomplished using measurement-based feedback schemes. The next step is to prepare and stabilize a state of a composite system. Here we demonstrate the stabilization of an entangled Bell state of a quantum register of two superconducting qubits for an arbitrary time. Our result is achieved using an autonomous feedback scheme that combines continuous drives along with a specifically engineered coupling between the two-qubit register and a dissipative reservoir. Similar autonomous feedback techniques have been used for qubit reset, single-qubit state stabilization, and the creation and stabilization of states of multipartite quantum systems. Unlike conventional, measurement-based schemes, the autonomous approach uses engineered dissipation to counteract decoherence, obviating the need for a complicated external feedback loop to correct errors. Instead, the feedback loop is built into the Hamiltonian such that the steady state of the system in the presence of drives and dissipation is a Bell state, an essential building block for quantum information processing. Such autonomous schemes, which are broadly applicable to a variety of physical systems, as demonstrated by the accompanying paper on trapped ion qubits, will be an essential tool for the implementation of quantum error correction.
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Affiliation(s)
- S Shankar
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - M Hatridge
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Z Leghtas
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - K M Sliwa
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - A Narla
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - U Vool
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - S M Girvin
- 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
| | - M Mirrahimi
- 1] Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA [2] INRIA Paris-Rocquencourt, Domaine de Voluceau, BP 105, 78153 Le Chesnay Cedex, France
| | - M H Devoret
- Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
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44
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Steffen L, Salathe Y, Oppliger M, Kurpiers P, Baur M, Lang C, Eichler C, Puebla-Hellmann G, Fedorov A, Wallraff A. Deterministic quantum teleportation with feed-forward in a solid state system. Nature 2013; 500:319-22. [PMID: 23955231 DOI: 10.1038/nature12422] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Accepted: 06/28/2013] [Indexed: 11/09/2022]
Abstract
Engineered macroscopic quantum systems based on superconducting electronic circuits are attractive for experimentally exploring diverse questions in quantum information science. At the current state of the art, quantum bits (qubits) are fabricated, initialized, controlled, read out and coupled to each other in simple circuits. This enables the realization of basic logic gates, the creation of complex entangled states and the demonstration of algorithms or error correction. Using different variants of low-noise parametric amplifiers, dispersive quantum non-demolition single-shot readout of single-qubit states with high fidelity has enabled continuous and discrete feedback control of single qubits. Here we realize full deterministic quantum teleportation with feed-forward in a chip-based superconducting circuit architecture. We use a set of two parametric amplifiers for both joint two-qubit and individual qubit single-shot readout, combined with flexible real-time digital electronics. Our device uses a crossed quantum bus technology that allows us to create complex networks with arbitrary connecting topology in a planar architecture. The deterministic teleportation process succeeds with order unit probability for any input state, as we prepare maximally entangled two-qubit states as a resource and distinguish all Bell states in a single two-qubit measurement with high efficiency and high fidelity. We teleport quantum states between two macroscopic systems separated by 6 mm at a rate of 10(4) s(-1), exceeding other reported implementations. The low transmission loss of superconducting waveguides is likely to enable the range of this and other schemes to be extended to significantly larger distances, enabling tests of non-locality and the realization of elements for quantum communication at microwave frequencies. The demonstrated feed-forward may also find application in error correction schemes.
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Affiliation(s)
- L Steffen
- Department of Physics, ETH Zurich, CH-8093 Zurich, Switzerland.
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45
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Quijandría F, Porras D, García-Ripoll JJ, Zueco D. Circuit QED bright source for chiral entangled light based on dissipation. PHYSICAL REVIEW LETTERS 2013; 111:073602. [PMID: 23992064 DOI: 10.1103/physrevlett.111.073602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2012] [Revised: 04/01/2013] [Indexed: 06/02/2023]
Abstract
We present a scalable and tunable framework for the quantum simulation of critical dissipative models based on a circuit QED cavity array interacting with driven superconducting qubits. We will show that the strongly correlated many-body state of the cavities can be mapped into the state of propagating photons in a transmission line. This allows not only for an efficient way of accessing the correlations in the many-body system, but also provides a bright source of chiral entangled light where directionality and entanglement are assisted by collective phenomena and breaking of reflection symmetry.
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Affiliation(s)
- Fernando Quijandría
- Instituto de Ciencia de Materiales de Aragón y Departamento de Física de la Materia Condensada, CSIC-Universidad de Zaragoza, Zaragoza E-50012, Spain
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46
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Carr AW, Saffman M. Preparation of entangled and antiferromagnetic states by dissipative Rydberg pumping. PHYSICAL REVIEW LETTERS 2013; 111:033607. [PMID: 23909322 DOI: 10.1103/physrevlett.111.033607] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 06/06/2013] [Indexed: 06/02/2023]
Abstract
We propose and analyze an approach for preparation of high fidelity entanglement and antiferromagnetic states using Rydberg mediated interactions with dissipation. Using asymmetric Rydberg interactions the two-atom Bell singlet is a dark state of the Rydberg pumping process. Master equation simulations demonstrate Bell singlet preparation fidelity F=0.998. Antiferromagnetic states are generated on a four-spin plaquette in agreement with results found from diagonalization of the transverse field Ising Hamiltonian.
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Affiliation(s)
- A W Carr
- Department of Physics, 1150 University Avenue, University of Wisconsin, Madison, Wisconsin 53706, USA
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47
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Abstract
The study of individual quantum systems in solids, for use as quantum bits (qubits) and probes of decoherence, requires protocols for their initialization, unitary manipulation, and readout. In many solid-state quantum systems, these operations rely on disparate techniques that can vary widely depending on the particular qubit structure. One such qubit, the nitrogen-vacancy (NV) center spin in diamond, can be initialized and read out through its special spin-selective intersystem crossing, while microwave electron spin resonance techniques provide unitary spin rotations. Instead, we demonstrate an alternative, fully optical approach to these control protocols in an NV center that does not rely on its intersystem crossing. By tuning an NV center to an excited-state spin anticrossing at cryogenic temperatures, we use coherent population trapping and stimulated Raman techniques to realize initialization, readout, and unitary manipulation of a single spin. Each of these techniques can be performed directly along any arbitrarily chosen quantum basis, removing the need for extra control steps to map the spin to and from a preferred basis. Combining these protocols, we perform measurements of the NV center's spin coherence, a demonstration of this full optical control. Consisting solely of optical pulses, these techniques enable control within a smaller footprint and within photonic networks. Likewise, this unified approach obviates the need for both electron spin resonance manipulation and spin addressability through the intersystem crossing. This method could therefore be applied to a wide range of potential solid-state qubits, including those which currently lack a means to be addressed.
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48
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Wenner J, Yin Y, Lucero E, Barends R, Chen Y, Chiaro B, Kelly J, Lenander M, Mariantoni M, Megrant A, Neill C, O'Malley PJJ, Sank D, Vainsencher A, Wang H, White TC, Cleland AN, Martinis JM. Excitation of superconducting qubits from hot nonequilibrium quasiparticles. PHYSICAL REVIEW LETTERS 2013; 110:150502. [PMID: 25167235 DOI: 10.1103/physrevlett.110.150502] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 03/04/2013] [Indexed: 06/03/2023]
Abstract
Superconducting qubits probe environmental defects such as nonequilibrium quasiparticles, an important source of decoherence. We show that "hot" nonequilibrium quasiparticles, with energies above the superconducting gap, affect qubits differently from quasiparticles at the gap, implying qubits can probe the dynamic quasiparticle energy distribution. For hot quasiparticles, we predict a non-negligible increase in the qubit excited state probability Pe. By injecting hot quasiparticles into a qubit, we experimentally measure an increase of Pe in semiquantitative agreement with the model and rule out the typically assumed thermal distribution.
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Affiliation(s)
- J Wenner
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - Yi Yin
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - Erik Lucero
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - R Barends
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - Yu Chen
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - B Chiaro
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - J Kelly
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - M Lenander
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - Matteo Mariantoni
- Department of Physics, University of California, Santa Barbara, California 93106, USA and California NanoSystems Institute, University of California, Santa Barbara, California 93106, USA
| | - A Megrant
- Department of Physics, University of California, Santa Barbara, California 93106, USA and Department of Materials, University of California, Santa Barbara, California 93106, USA
| | - C Neill
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - P J J O'Malley
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - D Sank
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - A Vainsencher
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - H Wang
- Department of Physics, University of California, Santa Barbara, California 93106, USA and Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - T C White
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - A N Cleland
- Department of Physics, University of California, Santa Barbara, California 93106, USA and California NanoSystems Institute, University of California, Santa Barbara, California 93106, USA
| | - John M Martinis
- Department of Physics, University of California, Santa Barbara, California 93106, USA and California NanoSystems Institute, University of California, Santa Barbara, California 93106, USA
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49
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Gasparinetti S, Solinas P, Pugnetti S, Fazio R, Pekola JP. Environment-governed dynamics in driven quantum systems. PHYSICAL REVIEW LETTERS 2013; 110:150403. [PMID: 25167233 DOI: 10.1103/physrevlett.110.150403] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Indexed: 06/03/2023]
Abstract
We show that the dynamics of a driven quantum system weakly coupled to the environment can exhibit two distinct regimes. While the relaxation basis is usually determined by the system+drive Hamiltonian (system-governed dynamics), we find that under certain conditions it is determined by specific features of the environment, such as, the form of the coupling operator (environment-governed dynamics). We provide an effective coupling parameter describing the transition between the two regimes and discuss how to observe the transition in a superconducting charge pump.
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Affiliation(s)
- S Gasparinetti
- Low Temperature Laboratory (OVLL), Aalto University, P.O. Box 15100, FI-00076 Aalto, Finland
| | - P Solinas
- Low Temperature Laboratory (OVLL), Aalto University, P.O. Box 15100, FI-00076 Aalto, Finland and COMP Centre of Excellence, Department of Applied Physics, Aalto University School of Science, P.O. Box 11000, 00076 Aalto, Finland
| | - S Pugnetti
- NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, I-56126 Pisa, Italy
| | - R Fazio
- NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, I-56126 Pisa, Italy
| | - J P Pekola
- Low Temperature Laboratory (OVLL), Aalto University, P.O. Box 15100, FI-00076 Aalto, Finland
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50
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Geerlings K, Leghtas Z, Pop IM, Shankar S, Frunzio L, Schoelkopf RJ, Mirrahimi M, Devoret MH. Demonstrating a driven reset protocol for a superconducting qubit. PHYSICAL REVIEW LETTERS 2013; 110:120501. [PMID: 25166782 DOI: 10.1103/physrevlett.110.120501] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Indexed: 06/03/2023]
Abstract
Qubit reset is crucial at the start of and during quantum information algorithms. We present the experimental demonstration of a practical method to force qubits into their ground state, based on driving appropriate qubit and cavity transitions. Our protocol, called the double drive reset of population, is tested on a superconducting transmon qubit in a three-dimensional cavity. Using a new method for measuring population, we show that we can prepare the ground state with a fidelity of at least 99.5% in less than 3 μs; faster times and higher fidelity are predicted upon parameter optimization.
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Affiliation(s)
- K Geerlings
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520-8284, USA
| | - Z Leghtas
- INRIA Paris-Rocquencourt, Domaine de Voluceau, B.P. 105, 78153 Le Chesnay cedex, France
| | - I M Pop
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520-8284, USA
| | - S Shankar
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520-8284, USA
| | - L Frunzio
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520-8284, USA
| | - R J Schoelkopf
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520-8284, USA
| | - M Mirrahimi
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520-8284, USA and INRIA Paris-Rocquencourt, Domaine de Voluceau, B.P. 105, 78153 Le Chesnay cedex, France
| | - M H Devoret
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520-8284, USA
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