# Bistability in a Mesoscopic Josephson Junction Array Resonator

## TL;DR

This paper experimentally studies stochastic switching in a mesoscopic Josephson junction array resonator, revealing how bistability and switching rates depend on pump strength, temperature, and readout, with implications for quantum measurement and control.

## Contribution

It demonstrates the observation of stochastic bistable switching in a Josephson junction array resonator at GHz frequencies with low photon numbers, highlighting the role of nonlinearity and coupling.

## Key findings

- Switching rates follow Kramer's law and vary from Hz to mHz.
- Bistability appears at very low photon numbers due to anharmonicity.
- Interplay of nonlinearity and coupling offers potential for quantum measurement applications.

## Abstract

We present an experimental investigation of stochastic switching of a bistable Josephson junctions array resonator with a resonance frequency in the GHz range. As the device is in the regime where the anharmonicity is on the order of the linewidth, the bistability appears for a pump strength of only a few photons. We measure the dynamics of the bistability by continuously observing the jumps between the two metastable states, which occur with a rate ranging from a few Hz down to a few mHz. The switching rate strongly depends on the pump strength, readout strength and the temperature, following Kramer's law. The interplay between nonlinearity and coupling, in this little explored regime, could provide a new resource for nondemolition measurements, single photon switches or even elements for autonomous quantum error correction.