Spatially Random Disorder in Unitary Fermion System in $(4-\epsilon)$-Dimensions and Effective Action at Finite Temperature

TL;DR

This paper investigates a non-relativistic fermion system with disorder near four dimensions, revealing an interacting disorder fixed point with Lifshitz scaling and analyzing the finite temperature effective action.

Contribution

It introduces the study of quenched disorder effects on non-relativistic fermions near four dimensions, identifying a new disorder fixed point and Lifshitz scaling behavior.

Findings

Discovery of an interacting disorder fixed point in $oldsymbol{ ext{d}=4-oldsymbol{ ext{epsilon}}}$ dimensions.

Correlation functions exhibit Lifshitz scaling with anisotropic exponent $z=2+oldsymbol{ ext{ extgamma}}_E$.

Finite temperature analysis of the effective action at the disorder fixed point.

Abstract

Non-relativistic conformal field theory is significant to understand various aspects of an ultra-cold system. In this paper, we study a non-relativistic system of two-component fermions interacting with a complex boson with Yukawa-like interactions near $d=4$-spatial dimensions in the presence of a quenched disorder. The homogeneous theory flows to an interacting fixed point describing a unitary fermion system. In the presence of the disorder, we find that the system has an interesting phase structure in the space of the coupling constants and exhibits an interacting disorder fixed point in $\epsilon$-expansion. The correlation function obeys Lifshitz scaling behaviour at the disorder fixed point with the anisotropic exponent being $z=2+\gamma_E$. We also study the disorder system at finite temperature and compute the leading contribution to the 1PI effective action.