Pairing in Asymmetric Many-Fermion Systems: Functional Renormalisation Group Approach

TL;DR

This paper uses the functional renormalisation group method to analyze pairing phenomena in asymmetric many-fermion systems, identifying phase transition points and mapping the phase diagram.

Contribution

It introduces a set of approximate flow equations for effective couplings in an imbalanced fermion system and explores the phase diagram at unitarity.

Findings

Identified critical mass and density mismatch values for phase transition.

Mapped the phase diagram at unitarity and nearby regimes.

Derived and solved flow equations for effective couplings.

Abstract

Functional renormalisation group approach is applied to a imbalanced many- fermion system with a short-range attractive force. Composite boson field is introduced to describe the pairing between different flavour fermions. A set of approximate flow equations for the effective couplings is derived and solved. We identify the critical values of mass and particle number density mismatch when the system undergoes a phase transition to a normal state and determine the phase diagram both at unitary regime and nearby.