Applicability of the Wigner functional approach to evolution of quantum fields
1 P.N. Lebedev Physics Institute of the Russian Academy of Sciences, Moscow, Russia
2 Moscow Engineering Physics Institute, Moscow, Russia
3 Moscow Institute of Physics and Technology, Moscow, Russia
Published online: 28 October 2016
Evolution of highly excited quantum field is considered in the framework of Keldysh formalism . It is demonstrated that leading order (LO) term of semiclassical approximation appears as well-known Classical Statistical Approximation (CSA). In simple case of spatially homogeneous scalar field analytical expressions for leading and next-to-leading (NLO) order are presented. It is shown that the range of applicability of CSA strongly depends on the properties of the initial state of the system.
© The Authors, published by EDP Sciences, 2016
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.