Limits in the characteristic-function description of non-Lindblad-type open quantum systems

Journal Article · Mon Aug 15 04:00:00 EDT 2005 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.72.024103· OSTI ID:20718229

Maniscalco, Sabrina ^[1]

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1. School of Pure and Applied Physics, University of KwaZulu-Natal, Durban 4041 (South Africa)

In this paper I investigate the usability of the characteristic functions for the description of the dynamics of open quantum systems focussing on non-Lindblad-type master equations. I consider, as an example, a non-Markovian generalized master equation containing a memory kernel which may lead to nonphysical time evolutions characterized by negative values of the density matrix diagonal elements [S. M. Barnett and S. Stenholm, Phys. Rev. A 64, 033808 (2001)]. The main result of the paper is to demonstrate that there exist situations in which the symmetrically ordered characteristic function is perfectly well-defined while the corresponding density matrix loses positivity. Therefore, nonphysical situations may not show up in the characteristic function. As a consequence, the characteristic function cannot be considered an alternative complete description of the non-Lindblad dynamics.

• OSTI ID: 20718229
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 2 Vol. 72; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
DENSITY MATRIX
FUNCTIONS
KERNELS
MARKOV PROCESS
MATRIX ELEMENTS
QUANTUM MECHANICS