Correlations in Two-Dimensional Vortex Liquids

TL;DR

This paper investigates the spatial correlations in two-dimensional vortex liquids within a superconducting film using high-temperature perturbation theory, revealing strong correlations above the vortex solidification temperature.

Contribution

It derives a closed-form perturbation expansion for the superfluid-density correlation function and evaluates contributions up to 10th order, comparing results with simulations.

Findings

Correlation functions agree with Monte Carlo simulations

Vortex liquid shows strong correlations above solidification temperature

Perturbation expansion effectively describes vortex correlations

Abstract

We report on a high temperature perturbation expansion study of the superfluid-density spatial correlation function of a Ginzburg-Landau-model superconducting film in a magnetic field. We have derived a closed form which expresses the contribution to the correlation function from each graph of the perturbation theory in terms of the number of Euler paths around appropriate subgraphs. We have enumerated all graphs appearing out to 10-th order in the expansion and have evaluated their contributions to the correlation function. Low temperature correlation functions, obtained using Pad\'{e} approximants, are in good agreement with Monte Carlo simulation results and show that the vortex-liquid becomes strongly correlated at temperatures well above the vortex solidification temperature.