The Lattice Fermi Surface

TL;DR

This paper investigates the 2+1 dimensional Nambu-Jona-Lasinio model at high density, finding no BCS gap but evidence of Kosterlitz-Thouless type superfluidity influenced by relativistic fermions.

Contribution

It provides the first simulation evidence of 2d superfluidity with relativistic fermions and identifies a novel universality class with critical behavior.

Findings

No BCS condensate or gap at high density

Observation of critical behavior with novel exponents

Superfluidity consistent with Kosterlitz-Thouless transition

Abstract

The Nambu - Jona-Lasinio model in 2+1 dimensions is simulated for non-zero baryon chemical potential with a diquark source term. No evidence for a BCS condensate or gap is seen at high density; rather, critical behaviour with novel exponents is observed, suggesting that 2d superfluidity as first described by Kosterlitz and Thouless is realised, but with the universality class determined by the presence of relativistic fermions.