Causal hydrodynamics of gauge theory plasmas from AdS/CFT duality

We study causal hydrodynamics (Israel-Stewart theory) of gauge theory plasmas from the AdS/CFT duality. Causal hydrodynamics requires new transport coefficients (relaxation times) and we compute them for a number of supersymmetric gauge theories including the N = 4 super Yang-Mills theory. However, the relaxation times obtained from the shear mode'' do not agree with the ones from the sound mode,'' which implies that the Israel- Stewart theory is not a sufficient framework to describe the gauge theory plasmas.