Summary: arXiv:hep­ph/0009026
v1
4
Sep
2000
NONEQUILIBRIUM FIELDS:
EXACT AND TRUNCATED DYNAMICS a
Gert Aarts
Institut fur theoretische Physik, Universitat Heidelberg
Philosophenweg 16, 69120 Heidelberg, Germany
The nonperturbative real-time evolution of quantum elds out of equilibrium is
often solved using a mean-eld or Hartree approximation or by applying eective
action methods. In order to investigate the validity of these truncations, we imple-
ment similar methods in classical scalar eld theory and compare the approximate
dynamics with the full nonlinear evolution. Numerical results are shown for the
early-time behaviour, the role of approximate xed points, and thermalization.
1 Testing truncations?
An understanding of the nonperturbative evolution of quantum elds away
from equilibrium is needed in many physical situations. Canonical examples
are the universe at the end of in ation and the early stages of a heavy-ion

Source: Aarts, Gert - Department of Physics, University of Wales Swansea

Collections: Physics