Supersymmetric BCS: Effects of an external magnetic field and spatial fluctuations of the gap

TL;DR

This paper investigates a supersymmetric BCS model, analyzing how external magnetic fields and spatial gap fluctuations influence superconducting properties, revealing differences from standard BCS theory in phase transition order and superconductor classification.

Contribution

It extends a supersymmetric BCS model by studying magnetic and spatial effects, providing insights into superconductor types and phase transition characteristics.

Findings

Determined magnetic penetration and coherence lengths in the supersymmetric model.

Identified differences in phase transition order compared to standard BCS.

Distinguished between type I and type II superconductors within the model.

Abstract

Recently an N=1 supersymmetric model of BCS superconductivity was proposed realizing spontaneous symmetry breaking of a U(1)_R symmetry. Due to scalar contributions the superconducting phase transition turned out to be first order rather than second order as in standard BCS theory. Here we consider the effects of an external magnetic field and spatial fluctuations of the gap in that model. This allows us to compute the magnetic penetration length and the coherence length, and also to distinguish between type I and type II superconductors. We compare the supersymmetric and standard relativistic BCS results, where the main differences come from the different orders of the phase transition.