Dissipation in the effective field theory for hydrodynamics: First order effects

TL;DR

This paper develops a model-independent effective field theory framework to incorporate dissipative effects in hydrodynamics, explicitly linking macroscopic parameters to microscopic constituents and re-deriving key relations for transport coefficients.

Contribution

It introduces a novel, symmetry-based approach to include dissipation in hydrodynamics within an effective field theory, connecting microscopic and macroscopic descriptions.

Findings

Identifies three key parameters for dissipation: bulk viscosity, shear viscosity, and heat conduction.

Re-derives Kubo relations for transport coefficients within this framework.

Provides a systematic method to characterize dissipation at low frequencies.

Abstract

We introduce dissipative effects in the effective field theory of hydrodynamics. We do this in a model-independent fashion by coupling the long-distance degrees of freedom explicitly kept in the effective field theory to a generic sector that "lives in the fluid", which corresponds physically to the microscopic constituents of the fluid. At linear order in perturbations, the symmetries, the derivative expansion, and the assumption that this microscopic sector is thermalized, allow us to characterize the leading dissipative effects at low frequencies via three parameters only, which correspond to bulk viscosity, shear viscosity, and--in the presence of a conserved charge--heat conduction. Using our methods we re-derive the Kubo relations for these transport coefficients.