Transport Coefficients from pQCD to the Hadron Resonance Gas at finite BSQ densities

Abstract

We calculate the shear viscosity, $\eta$, in two limits: perturbative QCD and an excluded-volume hadron resonance gas (HRG), at finite BSQ densities. Using an interpolation framework, we connect these regimes. In addition, we present results for (almost) next-to-leading order weak-coupling shear viscosity for QCD at finite ${\mu }_B$, and discuss the convergence of the perturbative series.

Comments: Accepted contribution to Quark Matter 2025