Density matrix formalism for interacting quantum fields
Abstract
We provide a description of interacting quantum fields in terms of density matrices for any occupation numbers in Fock space in a momentum basis. As a simple example, we focus on a real scalar field interacting with another real scalar field, and present a practicable formalism for directly computing the density matrix elements of the combined scalar-scalar system. For deriving the main formula, we use techniques from non-equilibrium quantum field theory like thermo field dynamics and the Schwinger-Keldysh formalism. Our results allow for studies of particle creation/annihilation processes at finite times and other non-equilibrium processes including those found in the theory of open quantum systems.
Cite
@article{arxiv.2210.06991,
title = {Density matrix formalism for interacting quantum fields},
author = {Christian Käding and Mario Pitschmann},
journal= {arXiv preprint arXiv:2210.06991},
year = {2023}
}
Comments
21 pages, 7 figures, as published in Universe. arXiv admin note: text overlap with arXiv:2204.08829