Using holography, we study the evolution of a spatially homogeneous, far from equilibrium, strongly coupled N = 4 supersymmetric Yang-Mills plasma with a non-zero charge density or a background magnetic field. This gauge theory problem corresponds, in the dual gravity description, to an initial value problem in Einstein-Maxwell theory with homogeneous but anisotropic initial conditions. We explore the dependence of the equilibration process on different aspects of the initial departure from equilibrium and, while controlling for these dependencies, examine how the equilibration dynamics are affected by the presence of a non-vanishing charge density or an external magnetic field. The equilibration dynamics are remarkably insensitive to the addition of even large chemical potentials or magnetic fields; the equilibration time is set primarily by the form of the initial departure from equilibrium. For initial deviations from equilibrium which are well localized in scale, we formulate a simple model for equilibration times which agrees quite well with our results.

Among the key features of hot and dense QCD matter produced in ultrarelativistic heavy-ion collisions at RHIC is its very low shear viscosity, indicative of the properties of a near-ideal fluid, and a large opacity demonstrated by jet energy loss measurements. In this work, we utilize a microscopic transport model based on the Boltzmann equation with quark and gluon degrees of freedom and cross sections calculated from perturbative quantum chromodynamics to simulate an ideal quark-gluon plasma in full thermal and chemical equilibrium. We then use the Kubo formalism to calculate the shear viscosity to entropy-density ratio of the medium as a function of temperature and system composition. One of our key results is that the shear viscosity over entropy-density ratio η/s becomes invariant to the chemical composition of the system when plotted as a function of energy-density instead of temperature.

The damping of high momentum excitations in strongly coupled maximally supersymmetric Yang-Mills plasma is studied. Previous calculations of the asymptotic behavior of the quasinormal mode spectrum are extended and clarified. We confirm that subleading corrections to the lightlike dispersion relation ω(q) = |q| have a universal |q| −1/3 form. Sufficiently narrow, weak planar shocks may be viewed as coherent superpositions of short wavelength quasinormal modes. The attenuation and evolution in profile of narrow planar shocks are examined as an application of our results.