2008/04/11 by Steven S. Gubser, Abhinav Nellore, Silviu S. Pufu +1 · 1 citation
Physics and Astronomy · #hep-th
paper · pdf · doi:10.1103/physrevlett.101.131601
published as Phys.Rev.Lett.101:131601,2008 · 5 pages, 1 figure
arxiv created 2008/04/11 · arxiv updated 2009/12/01
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 zeta/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 zeta/s near Tc. For constructions that exhibit a smooth cross-over, like QCD does, the rise in zeta/s is more modest. We conjecture that divergences in zeta/s for black hole horizons are related to extrema of the entropy density as a function of temperature.