Comment on "Voltage-Current Characteristics of the Two-Dimensional Gauge Glass Model"

TL;DR

This paper critiques Li's 1992 claim of a finite-temperature phase transition in the 2D gauge-glass model, arguing that the observed nonlinear current-voltage characteristics are due to single-junction effects rather than a phase transition.

Contribution

It clarifies that the nonlinear current-voltage characteristics reported are caused by single-junction effects, challenging previous interpretations of phase transition evidence.

Findings

Li's nonlinear CVC is a single-junction effect

No evidence of finite-temperature phase transition in the 2D gauge-glass model

Reinterpretation of previous experimental data

Abstract

Li (Phys. Rev. Lett. {\bf 69},1819 (1992)) has computed the current-voltage characteristics (CVC) of a disordered two-dimensional (2D) Josephson-junction array and claimed that his data(nonlinear CVC for small temperatures), gives evidence for a finite-temperature phase transition in the 2D gauge-glass model in contradiction to the result of equilibrium simulations. In this Comment I show that the nonlinear CVC, found by Li, is merely a single-junction effect.