Superconductor-metal transition in an ultrasmall Josephson junction biased by a noisy voltage source

TL;DR

This paper investigates how shot noise in a voltage source affects the quantum phase transition in an ultrasmall Josephson junction, transforming it from a superconductor-insulator to a superconductor-metal transition, with implications for understanding noise effects on quantum devices.

Contribution

It reveals how shot noise modifies the superconductor-insulator transition, inducing a superconductor-metal transition in ultrasmall Josephson junctions, and links IV characteristics to noise statistics.

Findings

Shot noise changes the nature of the quantum phase transition.

In the metallic phase, IV curves reflect the voltage distribution from shot noise.

In the superconducting phase, IV curves reveal electron counting statistics.

Abstract

Shot noise in a voltage source changes the character of the quantum (dissipative) phase transition in an ultrasmall Josephson junction: The superconductor-insulator transition transforms into the superconductor-metal transition. In the metallic phase the IV curve probes the voltage distribution generated by shot noise, whereas in the superconducting phase it probes the counting statistics of electrons traversing the noise junction.