7 research outputs found
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
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