Effects of three-body scattering processes on BCS-BEC crossover

TL;DR

This paper explores how three-body scattering processes influence the BCS-BEC crossover, revealing that such interactions can make the crossover nonreversible and lead to metastable states.

Contribution

It introduces the role of three-body interactions in the BCS-BEC crossover, showing their impact on the reversibility and stability of the transition.

Findings

Three-body interactions cause the crossover to become nonreversible.

Starting from a BEC state, crossover to BCS is possible.

Starting from BCS, the system transitions to a metastable state.

Abstract

We investigate the BCS-BEC crossover taking into account an additional three-body interaction, which is essentially the scattering between the Cooper pairs and the newly formed bosons. We show that if the two-body interaction is attractive, the presence of this additional three-body term makes the crossover process a nonreversible one. Starting from a stable Bose-Einstein condensate (BEC) state, crossover to BCS can be achieved; but if the BCS state is the starting point, instead of a stable BEC region, what the system crosses over to is a metastable condensed state.