Quantum Monte Carlo Study of a Disordered 2-D Josephson Junction Array

TL;DR

This study uses quantum Monte Carlo methods to analyze how disorder affects the superconducting-insulating transition in a 2D Josephson junction array, revealing the disappearance of lobe structures under strong disorder.

Contribution

It provides the first detailed quantum Monte Carlo analysis of disorder effects on the phase diagram of 2D Josephson junction arrays.

Findings

Lobe structures vanish with strong offset charge disorder

Results align with mean-field approximation predictions

Disorder in capacitive energies influences phase transition behavior

Abstract

We have studied the superconducting-insulating phase transition in a disordered two-dimensional Josephson junction array, using quantum Monte Carlo techniques. We consider disorder in both the capacitive energies and in the values of the offset charges. The calculated phase diagram shows that the lobe structure of the phase diagram disappears for sufficiently strong disorder in the offset charge. Our results agree quite well with previous calculations carried out using a mean-field approximation.