Fast Scramblers, Horizons and Expander Graphs

TL;DR

This paper models quantum horizon thermalization using local quantum systems on expander graphs, highlighting their fast scrambling properties and connection to the membrane paradigm via conformal transformations.

Contribution

It introduces expander graph-based models as a simple microscopic framework for fast thermalization on quantum horizons, linking graph theory with black hole physics.

Findings

Expander graphs naturally model fast scramblers.

Conformal transformation relates the model to the membrane paradigm.

Provides a microscopic basis for horizon thermalization.

Abstract

We propose that local quantum systems defined on expander graphs provide a simple microscopic model for thermalization on quantum horizons. Such systems are automatically fast scramblers and are motivated from the membrane paradigm by a conformal transformation to the so-called optical metric.