Entanglement Growth after a Global Quench in Free Scalar Field Theory

TL;DR

This paper analyzes how entanglement and Rényi entropy grow after a global quench in free scalar field theories across multiple dimensions and geometries, comparing numerical results with analytical models and discovering anomalous zero-mode effects.

Contribution

It provides a comprehensive numerical and analytical study of entanglement growth in free scalar theories post-quench across various geometries and dimensions, highlighting zero-mode effects.

Findings

Excellent agreement with quasiparticle model at large regions

Logarithmic entanglement growth from zero mode

Comparison across multiple geometries and dimensions

Abstract

We compute the entanglement and R\'enyi entropy growth after a global quench in various dimensions in free scalar field theory. We study two types of quenches: a boundary state quench and a global mass quench. Both of these quenches are investigated for a strip geometry in 1, 2, and 3 spatial dimensions, and for a spherical geometry in 2 and 3 spatial dimensions. We compare the numerical results for massless free scalars in these geometries with the predictions of the analytical quasiparticle model based on EPR pairs, and find excellent agreement in the limit of large region sizes. At subleading order in the region size, we observe an anomalous logarithmic growth of entanglement coming from the zero mode of the scalar.