Hydrodynamics of Sakai-Sugimoto model in the quenched approximation

We study transport properties of the finite temperature Sakai-Sugimoto model. The model represents a holographic dual to (4 + 1)-dimensional supersymmetric SU(N-c) gauge theory compactified on a circle with anti-periodic boundary conditions for fermions, coupled to N-f left-handed quarks and Nf right-handed quarks localized at different points on the compact circle. We analytically compute the speed of sound and the sound wave attenuation in the quenched approximation. Since confinement/deconfinement (and the chiral symmetry restoration) phase transitions are first order in this model, we do not see any signature of these phase transitions in the transport properties. (c) 2006 Elsevier B.V. All rights reserved.