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Vacuum-selected timescales in driven Josephson systems

Sebastian Allende, David Galvez-Poblete

TL;DR

The paper shows that the intrinsic timescale of a Josephson junction, set by the plasma frequency, can be controlled by dynamical vacuum selection under a high-frequency drive. By applying a Kapitza-like drive to the tunneling coupling between two condensates, the authors derive an effective potential with a drive-term that creates a possible antiphase vacuum, yielding vacuum-dependent plasma frequencies. The two stabilized vacua, 0 and π, confer distinct clocks: ω0 and ωπ, demonstrating a vacuum-controlled Josephson clock principle rather than a simple renormalization of parameters. This vacuum-selective timing offers a route to encode temporal order in the dynamical vacuum structure of coherent quantum 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.

Vacuum-selected timescales in driven Josephson systems

TL;DR

The paper shows that the intrinsic timescale of a Josephson junction, set by the plasma frequency, can be controlled by dynamical vacuum selection under a high-frequency drive. By applying a Kapitza-like drive to the tunneling coupling between two condensates, the authors derive an effective potential with a drive-term that creates a possible antiphase vacuum, yielding vacuum-dependent plasma frequencies. The two stabilized vacua, 0 and π, confer distinct clocks: ω0 and ωπ, demonstrating a vacuum-controlled Josephson clock principle rather than a simple renormalization of parameters. This vacuum-selective timing offers a route to encode temporal order in the dynamical vacuum structure of coherent quantum 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.
Paper Structure (1 section, 31 equations, 2 figures)

This paper contains 1 section, 31 equations, 2 figures.

Table of Contents

  1. Theoretical Model

Figures (2)

  • Figure 1: Dimensionless effective potential $V_{\text{eff}}/J_o$ as a function of the phase $\phi$, for different values of the driving parameter $\alpha \equiv J_1^2/2\chi J_o \Omega^2$. The case $\alpha=0$ corresponds to the undriven system ($J_1=0$). For $\alpha=0.5$, the driving is insufficient to stabilize the antiphase configuration. For $\alpha =1.5$, satisfying the condition of Eq. (18), the potential exhibits two minima at $\phi =0$ (inphase) and $\phi = \pi$ (antiphase).
  • Figure 2: Dimensionless Josephson plasma frequency $\tilde{\omega} = \omega\sqrt{\chi/J_o}$ versus $\alpha = J_1^2/2\chi J_o \Omega^2$ for the inphase and antiphase dynamical regimes.