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Quantum frequency locking and downconversion in a driven qubit-cavity system

Nathan, Frederik and Refael, Gil and Rudner, Mark S. and Martin, Ivar (2020) Quantum frequency locking and downconversion in a driven qubit-cavity system. Physical Review Research, 2 (4). Art. No. 043411. ISSN 2643-1564. doi:10.1103/PhysRevResearch.2.043411.

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We study a periodically driven qubit coupled to a quantized cavity mode. Despite its apparent simplicity, this system supports a rich variety of exotic phenomena, such as topological frequency conversion as recently discovered in Martin et al. [Phys. Rev. X 7, 041008 (2017)]. Here we report on a qualitatively different phenomenon that occurs in this platform, where the cavity mode's oscillations lock their frequency to a rational fraction r/q of the driving frequency Ω. This phenomenon, which we term quantum frequency locking, is characterized by the emergence of q-tuplets of stationary (Floquet) states whose quasienergies are separated by Ω/q, up to exponentially small corrections. The Wigner functions of these states are nearly identical, and exhibit highly regular and symmetric structure in phase space. Similarly to Floquet time crystals, these states underlie discrete time-translation symmetry breaking in the model. We develop a semiclassical approach for analyzing and predicting quantum frequency locking in the model, and use it to identify the conditions under which it occurs.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Nathan, Frederik0000-0001-9700-0231
Rudner, Mark S.0000-0002-5150-6234
Martin, Ivar0000-0002-2010-6449
Alternate Title:Quantum phase-locking and frequency down-conversion in a driven cavity-qubit system
Additional Information:© 2020 The Author(s). Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Received 8 April 2020; revised 19 November 2020; accepted 7 December 2020; published 23 December 2020. I.M. was supported by the Materials Sciences and Engineering Division, Basic Energy Sciences, Office of Science, U. S. Dept. of Energy. F.N. and M.S.R. are grateful to the Villum Foundation and the European Research Council (ERC) under the European Union Horizon 2020 Research and Innovation Programme (Grant Agreement No. 678862) for support. G.R. is grateful for NSF DMR Grant No. 1839271. G.R. is also grateful to the U. S. Department of Energy, Office of Science, Basic Energy Sciences under Award No. DE-SC0019166. NSF and DOE supported G.R.'s time commitment to the project in equal shares.
Group:Institute for Quantum Information and Matter
Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0019166
Villum FoundationUNSPECIFIED
European Research Council (ERC)678862
Issue or Number:4
Record Number:CaltechAUTHORS:20200519-080742316
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:103299
Deposited By: Tony Diaz
Deposited On:19 May 2020 16:22
Last Modified:16 Nov 2021 18:20

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