Effect of curvature squared corrections in AdS on the viscosity of the dual gauge theory

Abstract

We use the real-time finite-temperature AdS/CFT correspondence to compute the effect of general R 2 corrections to the gravitational action in AdS space on the shear viscosity of the dual gauge theory. The R 2 terms in AdS 5 are determined by the central charges of the CFT. We present an example of a four-dimensional gauge theory in which the conjectured lower bound of 1/4π on the viscosity-to-entropy ratio is violated for finite N. © 2009 SISSA.