Escape rate of metastable states in a driven NbN superconducting microwave resonator

TL;DR

This paper investigates the thermal instability and hot spot formation in a driven NbN superconducting microwave resonator, analyzing noise-induced state transitions both theoretically and experimentally.

Contribution

It provides a combined theoretical and experimental analysis of noise-activated escape rates in a nonlinear superconducting resonator, highlighting partial agreement between models and measurements.

Findings

Noise induces transitions between metastable states.

Theoretical and experimental escape rates show partial agreement.

Hot spot formation is driven by temperature fluctuations caused by noise.

Abstract

We study thermal instability and formation of local hot spots in a driven nonlinear NbN superconducting microwave resonator. White noise injected into the resonator results in transitions between the metastable states via a process consisting of two stages. In the first stage, the input noise entering the system induces fluctuations in the resonator mode. While, in the second one, these mode fluctuations result in phase transitions of the hot spot due to induced temperature fluctuations. The associated noise-activated escape rate is calculated theoretically, and also measured experimentally by means of driving the system into stochastic resonance. A comparison between theory and experiment yields a partial agreement.