Chiral restoration effects on the shear viscosity of a pion gas

Abstract

We investigate the shear viscosity of a pion gas in relativistic kinetic theory, using the Nambu-Jona-Lasinio model to construct the pion mass and the pi-pi interaction at finite temperature. Whereas at low temperatures the scattering properties and, hence, the viscosity are in agreement with lowest-order chiral perturbation theory, we find strong medium modifications in the crossover region. Here the system is strongly coupled and the scattering lengths diverge, similarly as for ultra-cold Fermi gases at a Feshbach resonance. As a consequence, the ratio eta/s is found to be strongly reduced as compared to calculations without medium-modified masses and scattering amplitudes. However, the quantitative results are very sensitive to the details of the applied approximations.

15 pages, 12 figures; v2: extended discussions of the dressed sigma propagator and the low-temperature limit, typos corrected, accepted version

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Cited by in corpus (11)

• Estimating transport coefficients in hot and dense quark matter
• Shear viscosity $\eta$ to electrical conductivity ${\sigma }_{el}$ ratio for an anisotropic QGP
• Transport coefficients of two-flavor quark matter from the Kubo formalism
• Momentum and its affiliated transport coefficients for a hot QCD matter in a strong magnetic field
• Momentum transport properties of a hot and dense QCD matter in a weak magnetic field
• In-medium viscous coefficients of a hot hadronic gas mixture
• Viscous properties of hot and dense QCD matter in the presence of a magnetic field
• Shear Viscosities from Kubo Formalism in a large-$N_{\mathrm{c}}$ Nambu--Jona-Lasinio Model
• Real-time observables from Euclidean thermal correlation functions
• In-medium thermal conductivity and diffusion coefficients of a hot hadronic gas mixture
• Finite size effect on Dissociation and Diffusion of chiral partners in Nambu-Jona-Lasinio model