Field Theory Approaches to Relativistic Hydrodynamics

TL;DR

This paper applies field theory methods to relativistic hydrodynamics, focusing on thermal fluctuations of spin two modes, using the Martin-Siggia-Rose technique to analyze complex fluctuation effects.

Contribution

It introduces a novel application of the Martin-Siggia-Rose technique to relativistic fluids, specifically addressing thermal fluctuations of spin two modes.

Findings

Thermal fluctuations significantly affect relativistic fluid dynamics.

The Martin-Siggia-Rose method effectively translates hydrodynamic problems into quantum field theory.

Analysis of spin two mode fluctuations provides new insights into relativistic fluid behavior.

Abstract

Just as non relativistic fluids, oftentimes we find relativistic fluids in situations where random fluctuations cannot be ignored, thermal and turbulent fluctuations being the most relevant examples. Because of the theory's inherent nonlinearity, fluctuations induce deep and complex changes in the dynamics of the system. The Martin-Siggia-Rose technique is a powerful tool that allows us to translate the original hydrodynamic problem into a quantum field theory one, thus taking advantage of the progress in the treatment of quantum fields out of equilibrium. To demonstrate this technique, we shall consider the thermal fluctuations of the spin two modes of a relativistic fluid, in a theory where hydrodynamics is derived by taking moments of the Boltzmann equation under the relaxation time approximation.