Entanglement Entropy across the Lattice-Continuum Correspondence

TL;DR

This paper develops a method to compute entanglement entropy of continuum quantum fields using lattice regularizations, clarifying divergence origins and providing a practical computational recipe.

Contribution

It extends the lattice-continuum correspondence to subregion algebras, enabling entropy calculations of boson and fermion theories purely from lattice data.

Findings

Entanglement entropy divergences are clarified through lattice-continuum correspondence.

A detailed recipe for entropy calculation in continuum theories is provided.

Lattice quantities can accurately approximate continuum entanglement entropy.

Abstract

This paper revisits standard calculations of free field entanglement entropy in light of the newly developed lattice-continuum correspondence. This correspondence prescribes an explicit method to extract an approximately continuum quantum field theory out of a fully regularized lattice theory. This prescription will here be extended to subregion algebras, and it will be shown how entropies of continuum boson and fermion theories can be computed by working purely with lattice quantities. This gives a clear picture of the origin of divergences in entanglement entropy while also presenting a concise and detailed recipe for calculating this important quantity in continuum theories.