We consider classes of translationally invariant black hole solutions whose equations of state closely resemble that of QCD at zero chemical potential. We use these backgrounds to compute the ratio ζ/s of bulk viscosity to entropy density. For a class of black holes that exhibits a first-order transition, we observe a sharp rise in ζ/s near Tc. For constructions that exhibit a smooth crossover, like QCD does, the rise in ζ/s is more modest. We conjecture that divergences in ζ/s for black hole horizons are related to extrema of the entropy density as a function of temperature.
ASJC Scopus subject areas
- Physics and Astronomy(all)