Entanglement Entropy for Relevant and Geometric Perturbations

TL;DR

This paper investigates how entanglement entropy in quantum field theories responds to relevant operator perturbations and geometric deformations, revealing new second-order effects and universal behaviors.

Contribution

It provides a second-order calculation of entanglement entropy for perturbed CFTs and uncovers unexpected geometric dependencies at second order.

Findings

Universal entanglement entropy computed to second order for relevant perturbations.

Discovery of surprising second-order geometric effects on entanglement entropy.

Enhanced understanding of entanglement structure in perturbed quantum field theories.

Abstract

We continue the study of entanglement entropy for a QFT through a perturbative expansion of the path integral definition of the reduced density matrix. The universal entanglement entropy for a CFT perturbed by a relevant operator is calculated to second order in the coupling. We also explore the geometric dependence of entanglement entropy for a deformed planar entangling surface, finding surprises at second order.