# Fluid Dynamics far from Local Equilibrium

## TL;DR

This paper introduces a new framework for fluid dynamics far from local equilibrium, demonstrating that hydrodynamic attractors govern the evolution even with large gradients across different theoretical models.

## Contribution

It develops a theoretical framework for far-from-equilibrium fluid dynamics and identifies hydrodynamic attractors in multiple models, extending traditional near-equilibrium theories.

## Key findings

- Hydrodynamic attractors exist far from equilibrium.
- Attractors are identified in rBRSSS, kinetic theory, and N=4 SYM.
- System approaches attractors rapidly regardless of initial conditions.

## Abstract

Fluid dynamics is traditionally thought to apply only to systems near local equilibrium. In this case, the effective theory of fluid dynamics can be constructed as a gradient series. Recent applications of resurgence suggest that this gradient series diverges, but can be Borel-resummed, giving rise to a hydrodynamic attractor solution which is well defined even for large gradients. Arbitrary initial data quickly approaches this attractor via non-hydrodynamic mode decay. This suggests the existence of a new theory of far-from-equilibrium fluid dynamics. In this work, the framework of fluid dynamics far from local equilibrium for conformal system is introduced, and the hydrodynamic attractor solutions for rBRSSS, kinetic theory in the relaxation time approximation, and strongly-coupled N=4 SYM are identified for a system undergoing Bjorken flow.