Field-Theoretical description of the crossover between BCS and BEC in a non-Fermi superconductor

TL;DR

This paper uses field-theoretical methods to analyze the continuous crossover from BCS superconductivity to Bose-Einstein condensation in a non-Fermi superconductor, highlighting the role of the Anderson propagator exponent.

Contribution

It introduces a field-theoretical framework to describe the BCS-BEC crossover in non-Fermi superconductors, emphasizing the influence of the Anderson propagator exponent on the interaction.

Findings

The crossover is continuous for non-zero exponent α.

For α=0, the system reduces to a Fermi liquid.

The repulsive interaction between composite bosons depends on α.

Abstract

Using the field-theoretical methods we studied the evolution from BCS description of a non-Fermi superconductor to that of Bose-Einstein condensation (BEC) in one loop approximation. We showed that the repulsive interaction between composite bosons is determined by the exponent $\alpha$ of the Anderson propagator in a two dimensional model. For $\a\neq 0$ the crossover is also continous and for $\a=0$ we obtain the case of the Fermi liquid.