Photon generation from quantum vacuum using a josephson metamaterial

P. Lähteenmäki, G.S. Paraoanu, Juha Hassel, P. Hakonen

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    Abstract

    When one of the parameters in the Euler-Lagrange equations of motion of a sys- tem is modulated, particles can be generated out of the quantum vacuum. This phenomenon is known as the dynamical Casimir effect, and it was recently realized experimentally in systems of superconducting circuits, for example by using modulated resonators made of coplanar waveg- uides, or arrays of superconducting quantum intereference devices (SQUIDs) forming a Josephson metamaterial. In this paper, we consider a simple electrical circuit model for dynamical Casimir effects, consisting of an LC resonator, with the inductor modulated externally at 10.8 GHz and with the resonant frequency tunable over a range of ±400MHz around 5.4 GHz. The circuit is analyzed classically using a circuit simulator (APLAC). We demonstrate that if an additional source of classical noise couples to the resonator (on top of the quantum vacuum), for example via dissipative "internal modes", then the resulting spectrum of the photons in the cavity will present two strongly asymmetric branches. However, according to the theory of the dynamical Casimir effect, these branches should be symmetric, a prediction which is confirmed by our ex- perimental data. The simulation presented here therefore shows that the origin of the photons generated in our experiment with Josephson metamaterials is the quantum vacuum, and not a spurious classical noise source.
    Original languageEnglish
    Title of host publicationProceedings
    Subtitle of host publicationProgress in Electromagnetics Research Symposium, PIERS 2013
    PublisherElectromagnetics Academy
    Pages151-153
    ISBN (Print)978-193414224-0
    Publication statusPublished - 2013
    MoE publication typeNot Eligible
    Event33rd Progress in Electromagnetics Research Symposium, PIERS 2013 - Taipei, Taiwan, Province of China
    Duration: 25 Mar 201328 Mar 2013
    Conference number: 33

    Conference

    Conference33rd Progress in Electromagnetics Research Symposium, PIERS 2013
    Abbreviated titlePIERS 2013
    CountryTaiwan, Province of China
    CityTaipei
    Period25/03/1328/03/13

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    Lähteenmäki, P., Paraoanu, G. S., Hassel, J., & Hakonen, P. (2013). Photon generation from quantum vacuum using a josephson metamaterial. In Proceedings: Progress in Electromagnetics Research Symposium, PIERS 2013 (pp. 151-153). Electromagnetics Academy.