AdS plane waves, entanglement and mutual information

TL;DR

This paper investigates how entanglement and mutual information behave in $AdS$ plane wave backgrounds, revealing unique growth and transition patterns that differ from ground and thermal states, with implications for understanding excited states in holography.

Contribution

It introduces a phenomenological scaling model for entanglement in $AdS$ plane waves and analyzes mutual information for different strip configurations, highlighting novel behaviors and transitions.

Findings

Mutual information grows with strip size in wide regimes and shows a disentangling transition.

In narrow regimes, results relate to entanglement thermodynamics.

Distinct behavior from ground and thermal states in mutual information transitions.

Abstract

$AdS$ plane wave backgrounds are dual to CFT excited states with energy momentum density $T_{++}=Q$. Building on previous work on entanglement entropy in these and nonconformal brane plane wave backgrounds, we first describe a phenomenological scaling picture for entanglement in terms of "entangling partons". We then study aspects of holographic mutual information in these backgrounds for two strip shaped subsystems, aligned parallel or orthogonal to the flux. We focus on the wide ($Ql^d\gg 1$) and narrow ($Ql^d\ll 1$) strip regimes. In the wide strip regime, mutual information exhibits growth with the individual strip sizes and a disentangling transition as the separation between the strips increases, whose behaviour is distinct from the ground and thermal states. In the narrow strip case, our calculations have parallels with "entanglement thermodynamics" for these $AdS$ plane wave deformations. We also discuss some numerical analysis.