Gravitational collapse of thin shells: Time evolution of the holographic entanglement entropy

TL;DR

This paper investigates the time evolution of holographic entanglement entropy during gravitational collapse of thin shells in AdS spacetime, revealing a universal linear growth regime and comparing exact results with common approximation methods.

Contribution

It provides an exact analysis of extremal surfaces crossing collapsing shells and evaluates the validity of Vaidya and quasistatic approximations in this context.

Findings

Holographic entanglement entropy exhibits a universal linear growth during collapse.

Exact extremal surfaces can be determined for collapsing shells in AdS.

Approximation schemes' validity regions are quantitatively characterized.

Abstract

We study the dynamics of gravitationally collapsing massive shells in AdS spacetime, and show in detail how one can determine extremal surfaces traversing them. The results are used to solve the time evolution of the holographic entanglement entropy in strongly coupled dual conformal gauge theory, which is is seen to exhibit a regime of linear growth independent of the shape of the boundary entangling region and the equation of state of the shell. Our exact results are finally compared to those of two commonly used approximation schemes, the Vaidya metric and the quasistatic limit, whose respective regions of validity are quantitatively determined.