# Exact time dependence of causal correlations and nonequilibrium density matrices in holographic systems

## TL;DR

This paper provides the first exact holographic calculations of causal correlations in driven nonequilibrium (2+1)D systems, revealing universal features governed by pump duration and temperature changes, and links horizon locations to causal correlations.

## Contribution

It introduces exact time-dependent calculations of causal correlations in holographic systems and connects horizon geometry to nonequilibrium correlations without prior gravity knowledge.

## Key findings

- Universal features depend only on pump duration and temperature changes.
- Horizon locations can be inferred from causal correlations.
- Exact calculations match simple prototype geometries.

## Abstract

We present the first exact calculations of the time dependence of causal correlations in driven nonequilibrium states in (2+1)-dimensional systems using holography. Comparing exact results with those obtained from simple prototype geometries that are parametrized only by a time dependent temperature, we find that the universal slowly varying features are controlled just by the pump duration and the initial and final temperatures only. We provide numerical evidence that the locations of the event and apparent horizons in the dual geometries can be deduced from the nonequilibrium causal correlations without any prior knowledge of the dual gravity theory.