Monte Carlo simulations of a disordered superconductor-metal quantum phase transition

TL;DR

This paper uses Monte Carlo simulations to study the quantum phase transition in a disordered nanowire from superconducting to metallic, revealing infinite-randomness critical behavior consistent with the random transverse-field Ising universality class.

Contribution

It provides numerical evidence supporting the infinite-randomness critical behavior and universality class of the disordered superconductor-metal transition.

Findings

Critical behavior is of infinite-randomness type.

Transition belongs to the random transverse-field Ising universality class.

Finite-size scaling confirms theoretical predictions.

Abstract

We investigate the quantum phase transitions of a disordered nanowire from superconducting to metallic behavior by employing extensive Monte Carlo simulations. To this end, we map the quantum action onto a (1+1)-dimensional classical XY model with long-range interactions in imaginary time. We then analyze the finite-size scaling behavior of the order parameter susceptibility, the correlation time, the superfluid density, and the compressibility. We find strong numerical evidence for the critical behavior to be of infinite-randomness type and to belong to the random transverse-field Ising universality class, as predicted by a recent strong disorder renormalization group calculation.