Superfluidity in multicomponent fermions via the functional renormalization group

TL;DR

This paper investigates the critical behavior of the phase transition to superfluidity in large spin fermionic systems using the functional renormalization group, revealing a fluctuation-induced first-order transition with varying discontinuity.

Contribution

It introduces a nonperturbative analysis of the phase transition in multicomponent fermions via the functional renormalization group, highlighting the fluctuation-induced first-order nature.

Findings

Established a fluctuation-induced first-order phase transition.

Identified a nearly continuous transition in the weak-coupling regime.

Detected a clear discontinuity in the transition at strong coupling.

Abstract

We reveal the critical properties of the phase transition towards superfluid order that has been proposed to occur in large spin fermionic systems. For this purpose, we consider the bosonic field theory for fluctuations of the complex skew-symmetric rank-2 tensor order parameter close to the transition. We then nonperturbatively determine the scale dependence of the couplings of the theory by means of the functional renormalization group. We established a fluctuation-induced first-order phase transition. In the weak-coupling regime the jump in the order parameter is small and a new phase occurs almost continuously, while in the strong one the discontinuity of the transition is well detectable.