Shear viscosity over entropy density ratio with extended quasi-particles

TL;DR

This paper explores how microscopic spectral properties influence macroscopic transport coefficients like shear viscosity and entropy density, analyzing the liquid-gas crossover and thermal constraints on fluidity in an effective field theory framework.

Contribution

It introduces an effective field theory approach linking spectral density to transport properties and examines the impact of many-particle correlations on fluid behavior.

Findings

Spectral density affects shear viscosity and entropy density.

Liquid-gas crossover impacts transport coefficients.

Thermal constraints limit the fluidity measure.

Abstract

We consider an effective field theory description of beyond-quasi-particle excitations aiming to associate the transport properties of the system with the spectral density of states. Tuning various properties of the many-particle correlations, we investigate how the robust microscopic features are translated into the macroscopic observables like shear viscosity and entropy density. The liquid-gas crossover is analysed using several examples. A thermal constraint on the fluidity measure, the ratio of shear viscosity to entropy density, is discussed.