Quantum circuit analog of the dynamical Casimir effect

Toshiyuki Fujii*, Shigemasa Matsuo, Noriyuki Hatakenaka, Susumu Kurihara, Anton Zeilinger


    研究成果: Article査読

    51 被引用数 (Scopus)


    We investigate a quantum-circuit analog of the dynamical Casimir effect discussed in cavity quantum electrodynamics (QED). A double superconducting quantum interference device (SQUID), consisting of a superconducting loop interrupted by a dc-SQUID, is regarded as a harmonic oscillator with a time-dependent frequency imitating the nonadiabatic boundaries in a cavity QED. Squeezing occurs due to parametric processes inherent in the system. We reformulate squeezing based on the Bogoliubov transformation between eigenstates at different times and derive the analytic formula for quantum-state evolutions of the system. The squeezing parameter clearly reveals the relationship between squeezing and nonadiabatic nature of the system. Thus, the squeezing parameter serves as a measure for the dynamical Casimir effect. We demonstrate squeezing for two types of frequency modulation and propose a method for measuring squeezing by using a circuit QED technique under coherent oscillations between an artificial atom and an LC circuit in the presence of dissipation. These observations suggest that a quantum circuit with a Josephson junction is a promising candidate for detecting the dynamical Casimir effect.

    ジャーナルPhysical Review B - Condensed Matter and Materials Physics
    出版ステータスPublished - 2011 11月 23

    ASJC Scopus subject areas

    • 凝縮系物理学
    • 電子材料、光学材料、および磁性材料


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