Anisotropic plasma at strong coupling and R-charge fluctuations

We briefly discuss our first attempt to describe an anisotropic quark-gluon plasma at strong coupling in the AdS/CFT correspondence framework. We constructed an exact dual gravity solution and found that despite the fact that it is singular it allows for a construction of natural incoming boundary conditions. A study of a small perturbation about this geometry shows that the dispersion relation depends strongly on the relative sign of the wave vector and the sign of the anisotropy. Yet, we did not encounter any instabilities

Non-equilibrium dynamics of QGP in AdS/CFT framework

Recently developed numerical method in AdS/CFT correspondence allows for simulation of strongly coupled non-equilibrium expanding N = 4 SYM fluid. This system serves as a testbed for RHIC and LHC quark-gluon plasma research, as well as a well-defined toy model of strongly coupled, non-perturbative non-Abelian gauge theory at finite temperature. Application of numerical tools allowed to gain some insight into the process of transition to hydrodynamic regime and also gave a few surprisingly simple characteristics of hydronization and thermalization process

The characteristics of thermalization of boost-invariant plasma from holography

We report on the approach towards the hydrodynamic regime of boost-invariant N=4 super Yang-Mills plasma at strong coupling starting from various far-from-equilibrium states at tau=0. The results are obtained through numerical solution of Einstein's equations for the dual geometries, as described in detail in the companion article arXiv:1203.0755. Despite the very rich far-from-equilibrium evolution, we find surprising regularities in the form of clear correlations between initial entropy and total produced entropy, as well as between initial entropy and the temperature at thermalization, understood as the transition to a hydrodynamic description. For 29 different initial conditions that we consider, hydrodynamics turns out to be definitely applicable for proper times larger than 0.7 in units of inverse temperature at thermalization. We observe a sizable anisotropy in the energy-momentum tensor at thermalization, which is nevertheless entirely due to hydrodynamic effects. This suggests that effective thermalization in heavy ion collisions may occur significantly earlier than true thermalization.Comment: 4 pages, 5 figures; see also the companion article arXiv:1203.0755; v2: figure corrected (fixes problem with Acrobat); v3: various clarifications and additional data points added; v4: typo fixed, publishe

A numerical relativity approach to the initial value problem in asymptotically Anti-de Sitter spacetime for plasma thermalization - an ADM formulation

This article studies a numerical relativity approach to the initial value problem in Anti-de Sitter spacetime relevant for dual non-equilibrium evolution of strongly coupled non-Abelian plasma undergoing Bjorken expansion. In order to use initial conditions for the metric obtained in arXiv:0906.4423 we introduce new, ADM formalism-based scheme for numerical integration of Einstein's equations with negative cosmological constant. The key novel element of this approach is the choice of lapse function vanishing at fixed radial position, enabling, if needed, efficient horizon excision. Various physical aspects of the gauge theory thermalization process in this setup have been outlined in our companion article arXiv:1103.3452. In this work we focus on the gravitational side of the problem and present full technical details of our setup. We discuss in particular the ADM formalism, the explicit form of initial states, the boundary conditions for the metric on the inner and outer edges of the simulation domain, the relation between boundary and bulk notions of time, the procedure to extract the gauge theory energy-momentum tensor and non-equilibrium apparent horizon entropy, as well as the choice of point for freezing the lapse. Finally, we comment on various features of the initial profiles we consider.Comment: 25 pages, 9 figures, 1 table; see also the companion article arXiv:1103.3452; v2: typos fixed; v3: references added and updated, publishe

Erfahrungen, Probleme und Aufgaben zur engen Verbindung der Grundlagenforschung an Einrichtungen der AdW und des Hochschulwesens der DDR mit Forschung und Entwicklung in den Kombinaten

ISVG 84.248 S / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman