Fermion mass generation without a condensate

TL;DR

This paper investigates a lattice model where fermions acquire mass at strong coupling without forming a traditional condensate, revealing a second order phase transition between massless and massive phases.

Contribution

It demonstrates the existence of massive fermions without bilinear condensates and provides Monte Carlo evidence for a direct second order phase transition.

Findings

Evidence for a second order phase transition

Massive fermions without condensate formation

Validation of theoretical predictions through simulations

Abstract

We study a lattice field theory model containing two flavors of massless staggered fermions with an onsite four-fermion interaction. The symmetry of the model forbids non-zero fermion bilinear order parameters that can generate a fermion mass. At weak couplings, we expect a massless fermion phase. At strong couplings, we can argue for the existence of massive fermions without the formation of any fermion bilinear condensate. Using Monte Carlo calculations in three space-time dimensions, we find evidence for a direct second order phase transition between the two phases.