# Sourced Carrollian Fluids Dual to Black Hole Horizons

## TL;DR

This paper explores the relationship between black hole horizon geometries and Carrollian fluids, demonstrating how perturbations lead to fluid equilibration and horizon relaxation, advancing understanding of horizon-fluid duality.

## Contribution

It introduces a perturbative approach linking horizon dynamics to Carrollian hydrodynamics with sources, revealing fluid equilibration processes during horizon relaxation.

## Key findings

- Horizon perturbations cause Carrollian fluid energy and momentum to approach equilibrium.
- The horizon's geometric expansion correlates with fluid equilibration.
- Horizon relaxation dynamics are connected to fluid behavior in Carrollian hydrodynamics.

## Abstract

The (degenerate) geometry of event horizons is linked to Carrollian fluids. We investigate the behavior of event horizons via a perturbative coupling to a massless scalar field, making connections to Carrollian hydrodynamics with a driving source, and discuss the fluid equilibration in tandem with the horizon's relaxation to equilibrium. We observe that after the perturbation dies off, the Carrollian fluid energy and momentum densities approach equilibrium as the horizon asymptotically becomes non-expanding. We connect the equilibration of the Carrollian fluid dual to the black hole horizon through the expansion of its background geometry.