Entanglement wedge reconstruction and correlation measures in mixed states: modular flows versus quantum recovery channels

TL;DR

This paper investigates how bulk geometry can be reconstructed from boundary mixed states using various tools like modular flow, recovery channels, and correlation measures, revealing connections and dynamics in holographic systems.

Contribution

It compares different correlation and reconstruction methods in mixed states, highlighting their relationships and effects on entanglement and complexity in holographic models.

Findings

Modular flow relates to entanglement and complexity of purification.

Uhlmann fidelity effectively measures correlations in mixed states.

Dynamics of correlations are linked to information speeds and void formation.

Abstract

In this work we study the nature of correlations among mixed states in the setup of two symmetric strips. We use various tools to determine how the bulk geometry could be reconstructed from the boundary mixed information. These tools would be the modular Hamiltonian and modular flow, OPE blocks, quantum recovery channels such as Petz map, Uhlmann holonomy and Wilson lines. We comment on the similarities and connections between these approaches in our symmetric setup of a mixed system. Specially, we use parameters such as dissipation which is being modeled by the mass of graviton, and also the same sign charge of the two strips to find connections between these different approaches. Then, using Uhlmann fidelity as the correlation measure, we look into the various types of correlations in mixed systems such as discord. Next, we use simple results of modular Hamiltonian for fermions to get insights about the relations between modular flow and entanglement and complexity of purification (EoP/CoP), and also behavior of modular flows in confining geometries. Finally, we study the dynamics of correlations using various information speeds and also model of void formation in CFTs and again we comment on their relationships with the behavior of EoP and CoP.