Information Scrambling Versus Quantum Revival Through the Lens of Operator Entanglement

TL;DR

This paper investigates quantum revivals and information scrambling in 2d conformal field theories using operator entanglement, revealing differences between free fermion and holographic CFTs and proposing a modified entanglement model.

Contribution

It demonstrates how operator mutual information reveals quantum revival in free CFTs but not in holographic CFTs, and introduces a modified line tension model linked to wormholes.

Findings

Quantum revival occurs in free fermion CFTs but not in holographic CFTs.

Finite size effects weaken information scrambling in holographic CFTs.

A modified line tension model explains entanglement dynamics and relates to wormholes.

Abstract

In this paper, we look for signatures of quantum revivals in two-dimensional conformal field theories (2d CFTs) on a spatially compact manifold by using operator entanglement. It is believed that thermalization does not occur on spatially compact manifolds as the quantum state returns to its initial state which is a phenomenon known as quantum revival. We find that in CFTs such as the free fermion CFT, the operator mutual information exhibits quantum revival in accordance with the relativistic propagation of quasiparticles while in holographic CFTs, the operator mutual information does not exhibit this revival and the quasiparticle picture breaks down. Furthermore, by computing the tripartite operator mutual information, we find that the information scrambling ability of holographic CFTs can be weakened by the finite size effect. We propose a modification of an effective model known as the line tension picture to explain the entanglement dynamics due to the strong scrambling effect and find a close relationship between this model and the wormhole (Einstein-Rosen Bridge) in the holographic bulk dual.