Transverse Momentum Differential Global Analysis of Heavy-Ion Collisions.

The understanding of heavy ion collisions and its quark-gluon plasma (QGP) formation requires a complicated interplay of rich physics in a wealth of experimental data. In this work we compare for identified particles the transverse momentum dependence of both the yields and the anisotropic flow coefficients for both PbPb and pPb collisions. We do this in a global model fit including a free streaming prehydrodynamic phase with variable velocity v_{fs}, thereby widening the scope of initial conditions. During the hydrodynamic phase we vary three second order transport coefficients. The free streaming velocity has a preference slightly below the speed of light. In this extended model the QGP bulk viscosity is small and even consistent with zero.

Strongly Coupled Anisotropic Gauge Theories and Holography.

We initiate a nonperturbative study of anisotropic, nonconformal, and confining gauge theories that are holographically realized in gravity by generic Einstein-axion-dilaton systems. In the vacuum, our solutions describe renormalization group flows from a conformal field theory in the UV to generic scaling solutions in the IR with generic hyperscaling violation and dynamical exponents θ and z. We formulate a generalization of the holographic c theorem to the anisotropic case. At finite temperature, we discover that the anisotropic deformation reduces the confinement-deconfinement phase transition temperature suggesting a possible alternative explanation of inverse magnetic catalysis solely based on anisotropy. We also study transport and diffusion properties in anisotropic theories and observe, in particular, that the butterfly velocity that characterizes both diffusion and growth of chaos transverse to the anisotropic direction saturates a constant value in the IR which can exceed the bound given by the conformal value.

Holographic QCD in the Veneziano Limit at a Finite Magnetic Field and Chemical Potential.

We investigate QCD-like gauge theories at strong coupling at a finite magnetic field B, temperature T, and quark chemical potential µ using the improved holographic QCD model, including the full backreaction of the quarks in the plasma. In addition to the phase diagram, we study the behavior of the quark condensate as a function of T, B, and µ and discuss the fate of (inverse) magnetic catalysis at a finite µ. In particular, we observe that inverse magnetic catalysis exists only for small values of the chemical potential. The speed of sound in this holographic quark-gluon plasma exhibits interesting dependence on the thermodynamic parameters.

Holographic Equilibration of Nonrelativistic Plasmas.

We study far-from-equilibrium physics of strongly interacting plasmas at criticality and zero charge density for a wide range of dynamical scaling exponents z in d dimensions using holographic methods. In particular, we consider homogeneous isotropization of asymptotically Lifshitz black branes with full backreaction. We find stable evolution and equilibration times that exhibit small dependence of z and are of the order of the inverse temperature. Performing a quasinormal mode analysis, we find a corresponding narrow range of relaxation times, fully characterized by the fraction z/(d-1). For z≥d-1, equilibration is overdamped, whereas for z

Deconfinement and gluon plasma dynamics in improved holographic QCD.

The thermodynamics of 5D dilaton gravity duals to confining gauge theories is analyzed. We show that they exhibit a first order Hawking-Page type phase transition. In the explicit background of improved holographic QCD of [U. Gursoy and E. Kiritsis, J. High Energy Phys. 02 (2008) 03210.1088/1126-6708/2008/02/032] [U. Gursoy, E. Kiritsis, and F. Nitti, J. High Energy Phys. 02 (2008) 01910.1088/1126-6708/2008/02/019], we find T_{c}=235 MeV. The temperature dependence of various thermodynamic quantities such as the pressure, entropy, and speed of sound is calculated. The results are in agreement with the corresponding lattice data.