# Chiral Separation Effect in lattice regularization

## TL;DR

This paper investigates the Chiral Separation Effect in lattice quantum field theories, comparing regularizations with and without exact chiral symmetry, and illustrating the effects with Wilson, overlap, and naive fermions.

## Contribution

It provides a detailed analysis of how the Chiral Separation Effect manifests or disappears depending on the lattice regularization and chiral symmetry properties.

## Key findings

- CSE appears in regularizations without exact chiral symmetry.
- CSE vanishes in exact chiral symmetry regularizations due to fermion doublers.
- Modified overlap regularization cancels CSE contributions through zeros and poles of the Green function.

## Abstract

We consider Chiral Separation Effect (CSE) in the lattice regularized quantum field theory. We discuss two types of regularization - with and without exact chiral symmetry. In the latter case this effect is described by its conventional expression for the massless fermions. This is illustrated by the two particular cases - of Wilson fermions and of the conventional overlap fermions. At the same time in the presence of the exact chiral symmetry the CSE disappears. This is illustrated by the naive lattice fermions, when the contributions of the fermion doublers cancel each other. Another example is the modified version of the overlap regularization proposed recently, where there is the exact chiral symmetry, but as a price for this the fermion doublers become zeros of the Green function. In this case the contribution to the CSE of zeros and poles of the Green function cancel each other.