Orateur
Description
Heavy quarkonia are considered among the most promising probes of quark
gluon plasma (QGP) formed in ultra relativistic heavy ion collisions (URHIC).
For a reliable use of such probe, we need a rigorous formalism which could
describe the real time and out of equilibrium evolution of in-medium quarkonia
while it keeps a full track of the quantum nature of our system, as well, being
derived from first principles. In addition, the formalism should consider the
static as well dynamical effects of QGP on heavy quarkonia on equal footing.
Among the possible formalisms, the open quantum systems outstand due to its
simplicity. Within this framework, the evolution of our system is governed by
quantum master equation which, by implementing semi classical approximations
(SCA), results into the standard and the more simple semi classical transport
equations as Boltzmann and Fokker-Planck / Langevin equations. Those last
had already shown, prior to the use of open quantum system techniques, a
good success in describing in medium quarkonia transport, in spite of their
model dependence in considering some QGP effects. Therefore, starting from
the fact that the semi classical transport equations are approximates of, the
more fundamental, quantum master equations, it is legitimate to wonder about
their range of validity and a quantitative comparison between the full quantum
and semi classical descriptions become mandatory to put our understanding of
in-medium quarkonia transport on stronger ground. In this talk, we review
briefly the derivation of quantum master equation in the quantum Brownian
regime and its associated semi classical Fokker-Planck / Langevin equation.
Then, for the sake of testing the validity of SCA, we discuss some comparative
results issued from one dimensional resolution of the two equations and draw
some conclusions on SCA validity.
