Non-perturbative Effects Near the Upper Critical Field in Type-II Superconductors

TL;DR

This paper demonstrates that perturbation theory fails near the upper critical field in type-II superconductors, revealing unusual behavior at the phase transition that challenges conventional calculations.

Contribution

It introduces a non-perturbative analysis of the behavior of type-II superconductors near the upper critical field, highlighting the limitations of traditional perturbative methods.

Findings

Perturbation theory breaks down near the upper critical field.

Unusual behavior observed at the phase transition.

Conventional calculations are insufficient near critical points.

Abstract

The properties of a conventional type-II superconductor near the upper critical field are usually calculated using a perturbative expansion in the strength of the order parameter. Here we show that perturbation theory breaks down near the upper critical field and that this breakdown leads to unusual behavior near the phase transition.