Universal corrections to entanglement entropy of local quantum quenches

TL;DR

This paper investigates universal corrections to entanglement entropy after local quantum quenches in 2D conformal field theories, revealing universal behavior at order  in the quench width and matching holographic predictions.

Contribution

It demonstrates the universality of -order corrections to entanglement entropy in local quenches, connecting CFT calculations with holographic and higher spin theories.

Findings

-order correction determined by stress tensor expectation value

Holographic entanglement entropy correction matches CFT prediction

Universal -order correction in theories with higher spin symmetry

Abstract

We study the time evolution of single interval Renyi and entanglement entropies following local quantum quenches in two dimensional conformal field theories at finite temperature for which the locally excited states have a finite temporal width, \epsilon. We show that, for local quenches produced by the action of a conformal primary field, the time dependence of Renyi and entanglement entropies at order \epsilon^2 is universal. It is determined by the expectation value of the stress tensor in the replica geometry and proportional to the conformal dimension of the primary field generating the local excitation. We also show that in CFTs with a gravity dual, the \epsilon^2 correction to the holographic entanglement entropy following a local quench precisely agrees with the CFT prediction. We then consider CFTs admitting a higher spin symmetry and turn on a higher spin chemical potential \mu. We calculate the time dependence of the order \epsilon^2 correction to the entanglement entropy for small \mu, and show that the contribution at order \mu^2 is universal. We verify our arguments against exact results for minimal models and the free fermion theory.