Dissipate locally, couple globally: a sharp transition from decoupling to infinite range coupling in Josephson arrays with on-site dissipation

TL;DR

This paper investigates the quantum phase transition in Josephson arrays with on-site dissipation, revealing a unique transition where all inter-grain couplings become relevant simultaneously, leading to a diverging correlation length.

Contribution

It introduces a novel transition in Josephson arrays with on-site dissipation, showing all couplings become relevant at once, unlike previous bond dissipation cases.

Findings

All inter-grain couplings become relevant simultaneously.

The transition exhibits a diverging spatial correlation length.

Floating phases are robust in dissipative quantum systems.

Abstract

We study the T=0 normal to superconducting transition of Josephson arrays with {\it on-site} dissipation. A perturbative renormalization group solution is given. Like the previously studied case of {\it bond} dissipation (BD), this is a "floating" to coupled (FC) phase transition. {\it Unlike} the BD transition, at which {\it only} nearest-neighbor couplings become relevant, here {\it all} inter-grain couplings, out to {\it infinitely} large distances, do so simultaneously. We predict, for the first time in an FC transition, a diverging spatial correlation length. Our results show the robustness of floating phases in dissipative quantum systems.