Squeezing of a quantum flux in a double rf-SQUID system

Kohji Takashima, Shigemasa Matsuo, Toshiyuki Fujii, Noriyuki Hatakenaka, Susumu Kurihara, Anton Zeilinger

    Research output: Contribution to journalArticle

    10 Citations (Scopus)

    Abstract

    We investigate the nonstationary boundary effect for a quantum flux in a double rf-SQUID system. In a superconducting ring interrupted by a dc-SQUID (so-called double rf-SQUID), the Josephson potential can be controlled by the magnetic flux through the dc-SQUID ring. This system is equivalent to an anharmonic oscillator with a time-dependent frequency. A rapid change of the magnetic flux in the dc-SQUID leads to the nonadiabatic mixing of the quantum states for a quantum flux in a double rf-SQUID. Therefore, this becomes a circuit analogue of the dynamical Casimir effect in quantum field theory. We perform numerical calculations for the quantum state evolution of the quantum flux within a harmonic approximation, taking account of the nonadiabatic effect. We found that the resulting state distribution has a super-Poissonian character that reflects flux squeezing caused by the Bogoliubov transformation between eigenstates at different times.

    Original languageEnglish
    Article number052260
    JournalJournal of Physics: Conference Series
    Volume150
    Issue number5
    DOIs
    Publication statusPublished - 2009

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    compressing
    magnetic flux
    analog circuits
    rings
    eigenvectors
    oscillators
    harmonics
    approximation

    ASJC Scopus subject areas

    • Physics and Astronomy(all)

    Cite this

    Takashima, K., Matsuo, S., Fujii, T., Hatakenaka, N., Kurihara, S., & Zeilinger, A. (2009). Squeezing of a quantum flux in a double rf-SQUID system. Journal of Physics: Conference Series, 150(5), [052260]. https://doi.org/10.1088/1742-6596/150/5/052260

    Squeezing of a quantum flux in a double rf-SQUID system. / Takashima, Kohji; Matsuo, Shigemasa; Fujii, Toshiyuki; Hatakenaka, Noriyuki; Kurihara, Susumu; Zeilinger, Anton.

    In: Journal of Physics: Conference Series, Vol. 150, No. 5, 052260, 2009.

    Research output: Contribution to journalArticle

    Takashima, K, Matsuo, S, Fujii, T, Hatakenaka, N, Kurihara, S & Zeilinger, A 2009, 'Squeezing of a quantum flux in a double rf-SQUID system', Journal of Physics: Conference Series, vol. 150, no. 5, 052260. https://doi.org/10.1088/1742-6596/150/5/052260
    Takashima K, Matsuo S, Fujii T, Hatakenaka N, Kurihara S, Zeilinger A. Squeezing of a quantum flux in a double rf-SQUID system. Journal of Physics: Conference Series. 2009;150(5). 052260. https://doi.org/10.1088/1742-6596/150/5/052260
    Takashima, Kohji ; Matsuo, Shigemasa ; Fujii, Toshiyuki ; Hatakenaka, Noriyuki ; Kurihara, Susumu ; Zeilinger, Anton. / Squeezing of a quantum flux in a double rf-SQUID system. In: Journal of Physics: Conference Series. 2009 ; Vol. 150, No. 5.
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