Vacuum-selected timescales in driven Josephson systems

Abstract In this work, we demonstrate that the intrinsic timescale of a Josephson junction can be controlled through dynamical vacuum selection. By applying a Kapitza-like high-frequency drive to the system, the effective Josephson potential is reshaped, allowing for the stabilization of inphase or antiphase configuration. As a result, the Josephson plasma frequency, that is, the clock frequency of the junction, becomes a tunable property of the selected vacuum. Our findings establish a vacuum-controlled Josephson clock principle, in which the dynamical vacuum acts as an internal reference that fixes the operational timescale of Josephson oscillations, rather than this scale being imposed externally. Our results open a route toward a vacuum-controlled temporal functionality in Josephson systems, where the intrinsic dynamical timescale is determined by the configuration around which the phase dynamics is organized.