Discrete-time construction of nonequilibrium path integrals on the Kostantinov–Perel' time contour. (29th May 2019)

• Record Type: Journal Article
• Authors: Secchi, Andrea; Polini, Marco
• Is Part Of: Journal of physics. Volume 52:Number 25(2019)
• Publication Date: 2019-05-29
• Subjects: nonequilibrium -- path integrals -- time contours; Mathematical physics -- Periodicals; Statistical physics -- Periodicals; Quantum theory -- Periodicals; Matter -- Properties -- Periodicals; 530.105
• DOI: 10.1088/1751-8121/ab2080
• Languages: English
• ISSNs: 1751-8113

Abstract

Abstract: Rigorous nonequilibrium actions for the many-body problem are usually derived by means of path integrals combined with a discrete temporal mesh on the Schwinger–Keldysh time contour. The latter suffers from a fundamental limitation: the initial state on this contour cannot be arbitrary, but necessarily needs to be described by a non-interacting density matrix, while interactions are switched on adiabatically. The Kostantinov–Perel' contour overcomes these and other limitations, allowing generic initial-state preparations. In this article, we apply the technique of the discrete temporal mesh to rigorously build the nonequilibrium path integral on the Kostantinov–Perel' time contour.