Exact Chiral Fermions and Finite Density on Lattice

TL;DR

This paper demonstrates that certain lattice actions for Overlap and Domain Wall Fermions at finite density avoid mu^2-divergences but break chiral symmetry, with numerical evidence showing effective continuum limits at coarser lattices.

Contribution

It analytically proves the absence of mu^2-divergences in a class of actions and numerically shows the feasibility of reaching the continuum limit with coarser lattices for specific parameter ranges.

Findings

mu^2-divergences are absent for these actions

Chiral invariance is violated in these formulations

Continuum limit can be achieved with coarser lattices for M in 1.5-1.6

Abstract

Any mu^2-divergence is shown analytically to be absent for a class of actions for Overlap and Domain Wall Fermions with nonzero chemical potential. All such actions are, however, shown to violate the chiral invariance. While the parameter M of these actions can be shown to be irrelevant in the continuum limit, as expected, it is shown numerically that the continuum limit can be reached with relatively coarser lattices for M in the range of 1.5-1.6.