Superconducting to normal state phase boundary in arrays of ultrasmall Josephson junctions

TL;DR

This paper investigates the phase boundary between superconducting and normal states in 2D arrays of ultrasmall Josephson junctions, combining analytical and numerical methods to match experimental results.

Contribution

It introduces a combined WKB renormalization group and Quantum Monte Carlo approach to analyze phase transitions in ultrasmall Josephson junction arrays.

Findings

Successful comparison with experimental data

Identification of the phase boundary in ultrasmall junction arrays

Insights into the competition between Josephson and charging energies

Abstract

We study the competition between Josephson and charging energies in two-dimensional arrays of ultrasmall Josephson junctions, when the mutual capacitance is dominant over the self-capacitance. Our calculations involve a combination of an analytic WKB renormalization group approach plus nonperturbative Quantum Monte Carlo simulations. We consider the zero frustration case in detail and we are able to make a successful comparison between our results and those obtained experimentally.