Microwave-induced thermal escape in Josephson junctions

TL;DR

This paper explores how microwave radiation influences thermal escape in Josephson junctions, revealing multi-valued switching currents and confirming the phenomena through experiments and simulations.

Contribution

It demonstrates the resonance effects of microwave signals on Josephson junctions and validates the classical thermal activation model with experimental and numerical evidence.

Findings

Resonance with Josephson plasma frequency causes multi-valued switching currents.

Good agreement between experimental data and numerical simulations.

Thermal activation processes are significantly affected by microwave radiation.

Abstract

We investigate, by experiments and numerical simulations, thermal activation processes of Josephson tunnel junctions in the presence of microwave radiation. When the applied signal resonates with the Josephson plasma frequency oscillations, the switching current may become multi-valued in a temperature range far exceeding the classical to quantum crossover temperature. Plots of the switching currents traced as a function of the applied signal frequency show very good agreement with the functional forms expected from Josephson plasma frequency dependencies on the bias current. Throughout, numerical simulations of the corresponding thermally driven classical Josephson junction model show very good agreement with the experimental data.