Speaker
Dr
Marcus Bluhm
(Laboratoire SUBATECH)
Description
By means of high energy nuclear collisions, the properties, such as
the viscosity coefficients, of QCD matter under extreme conditions
are intended to be experimentally revealed. One remarkable result
from collisions at RHIC is that the produced hot matter is an
almost ideal fluid, obeying the smallest shear viscosity to entropy
density ratio observed in nature. Employing an effective kinetic
theory for quasiparticle excitations featuring dynamically
generated self-energies, we determine the temperature dependence
of the viscosity coefficients of deconfined strongly interacting
matter [1,2]. This knowledge may serve as input for the
phenomenological description of heavy-ion collisions at LHC and
RHIC.
Exhibiting the parametric dependencies known from perturbative QCD
at large temperatures, the extrapolation of our results into the
non-perturbative region shows fairly nice quantitative agreement
with lattice QCD results in the case of a pure gluon plasma. We
find a minimum in the specific shear viscosity and a rapid increase
of the specific bulk viscosity near the deconfinement transition
temperature T_c. The ratio of bulk to shear viscosity comprises
both, a quadratic dependence on the conformality measure at large
temperatures as known from pQCD as well as a linear dependence
near T_c as known from specific strongly coupled and nearly
conformal theories based on gauge/string duality [3]. Thus, the
exploited framework provides a systematic interpolation between
both regimes of weak and strong coupling.
[1] M. Bluhm, B. Kampfer, K. Redlich, Nucl. Phys. A 830 (2009) 737C
[2] M. Bluhm, B. Kampfer, K. Redlich, arXiv:1011.5634
[3] M. Bluhm, B. Kampfer, K. Redlich, arXiv:1101.3072
Primary author
Dr
Marcus Bluhm
(Laboratoire SUBATECH)
Co-authors
Prof.
Burkhard Kampfer
(Helmholtz-Zentrum Dresden-Rossendorf & Technical University Dresden)
Prof.
Krzysztof Redlich
(Wroclaw University)
