title: Photon generation in an electromagnetic cavity with a time-dependent boundary.
abstract: We report the observation of photon generation in a microwave cavity with a time-dependent boundary condition. Our system is a microfabricated quarter-wave coplanar waveguide cavity. The electrical length of the cavity is varied by using the tunable inductance of a superconducting quantum interference device. It is measured at a temperature significantly less than the resonance frequency. When the length is modulated at approximately twice the static resonance frequency, spontaneous parametric oscillations of the cavity field are observed. Time-resolved measurements of the dynamical state of the cavity show multiple stable states. The behavior is well described by theory. Our results may be considered a preliminary step towards demonstrating the dynamical Casimir effect.
authors.affiliation: Microtechnology and Nanoscience, Chalmers University of Technology, S-41296 Göteborg, Sweden.
authors.forename: C M
authors.initials: CM
authors.lastname: Wilson
authors.forename: T
authors.initials: T
authors.lastname: Duty
authors.forename: M
authors.initials: M
authors.lastname: Sandberg
authors.forename: F
authors.initials: F
authors.lastname: Persson
authors.forename: V
authors.initials: V
authors.lastname: Shumeiko
authors.forename: P
authors.initials: P
authors.lastname: Delsing