Wednesday, February 8, 2012

1202.1301 (Marco Drewes et al.)

Boltzmann Equations from First Principles without Gradient Expansion    [PDF]

Marco Drewes, Sebastian Mendizabal, Christoph Weniger
We show from first principles the emergence of classical Boltzmann equations for a generic quantum field that couples to a collection of background fields and sources. Our analysis is based on relativistic nonequilibrium quantum field theory as described by the Kadanoff-Baym equations and does not rely on the usual semi-classical approximations, i.e. on-shell condition, close-to-equilibrium assumption, gradient expansion and the Kadanoff-Baym ansatz. Instead, we find simple analytical solutions to the full Kadanoff-Baym equations by using the Wentzel-Kramers-Brillouin (WKB) method, and discuss under which circumstances Boltzmann behavior emerges.
View original: http://arxiv.org/abs/1202.1301

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