Fluctuation induced non-canonical BCS states: a mechanism for pseudogap

TL;DR

This paper explores how statistical fluctuations causing non-unitary evolution in the BCS model can lead to non-canonical equilibrium states, providing a potential explanation for the pseudogap phenomenon.

Contribution

It introduces a mechanism where fluctuation-induced non-unitary dynamics result in non-canonical states, offering a new perspective on the pseudogap in superconductors.

Findings

Fluctuations induce non-unitary evolution in the BCS model.

Equilibrium states deviate from the canonical form due to fluctuations.

The pseudogap phenomenon can emerge from this fluctuation-driven mechanism.

Abstract

We pose the question of what effect the statistical fluctuation causes if it induces a non-unitary evolution. We apply this idea to the BCS model and study fluctuation around the mean-field average. We find that, dynamics of the thermalization influences the equilibrium besides the non-unitary evolution, and the resulting equilibrium state is no longer the canonical one. The pseudogap phenomenon can exist in this model.