Steady-state Physics, Effective Temperature Dynamics in Holography

TL;DR

This paper uses holography to develop an effective thermodynamic framework for out-of-equilibrium steady states driven by electric fields, introducing an effective temperature and entropy that describe macroscopic physics.

Contribution

It introduces a novel holographic approach to describe steady states with an effective temperature and entropy, extending thermodynamics to out-of-equilibrium systems.

Findings

Effective temperature exceeds background temperature.

Scaling behaviors for conformal theories.

Effective temperature relates to physical parameters at high electric fields.

Abstract

Using the gauge-gravity duality, we argue that for a certain class of out-of-equilibrium steady-state systems in contact with a thermal background at a given temperature, the macroscopic physics can be captured by an effective thermodynamic description. The steady-state is obtained by applying a constant electric field that results in a stationary current flow. Within holography, we consider generic probe systems where an open string equivalence principle and an open string metric govern the effective thermodynamics. This description comes equipped with an effective temperature, which is larger than the background temperature, and a corresponding effective entropy. For conformal or scale-invariant theories, certain scaling behaviours follow immediately. In general, in the large electric field limit, this effective temperature is also observed to obey generic relations with various physical parameters in the system.