# Correlations far from equilibrium in charged strongly coupled fluids subjected to a strong magnetic field

## TL;DR

This study uses a holographic model to analyze how charged, strongly coupled fluids thermalize under a magnetic field, revealing scale-dependent differences in the thermalization times of correlation functions.

## Contribution

It provides new insights into the thermalization process of charged strongly coupled systems under magnetic fields, highlighting the emergence of a universal saturation time for 2-point functions.

## Key findings

- Thermalization times for 2-point functions are about three times longer than for 1-point functions.
- Magnetic field and charge increase the thermalization times.
- A universal saturation time emerges at strong magnetic fields for 2-point functions.

## Abstract

Within a holographic model, we calculate the time evolution of 2-point and 1-point correlation functions (of selected operators) within a charged strongly coupled system of many particles. That system is thermalizing from an anisotropic initial charged state far from equilibrium towards equilibrium while subjected to a constant external magnetic field. One main result is that thermalization times for 2-point functions are significantly (approximately three times) larger than those of 1-point functions. Magnetic field and charge amplify this difference, generally increasing thermalization times. However, there is also a competition of scales between charge density, magnetic field, and initial anisotropy, which leads to an array of qualitative changes on the 2- and 1-point functions. There appears to be a strong effect of the medium on 2-point functions at early times, but approximately none at later times. At strong magnetic fields, an apparently universal thermalization time emerges, at which all 2-point functions appear to thermalize regardless of any other scale in the system. Hence, this time scale is referred to as saturation time scale. As extremality is approached in the purely charged case, 2- and 1-point functions appear to equilibrate at infinitely late time. We also compute 2-point functions of charged operators. Our results can be taken to model thermalization in heavy ion collisions, or thermalization in selected condensed matter systems.