Path-integral description of combined Hamiltonian and non-Hamiltonian dynamics in quantum dissipative systems

Titelangaben

Barth, Andreas M. ; Vagov, Alexei ; Axt, Vollrath Martin:
Path-integral description of combined Hamiltonian and non-Hamiltonian dynamics in quantum dissipative systems.
In: Physical Review B. Bd. 94 (2016) Heft 12 . - 125439.
ISSN 0163-1829
DOI: https://doi.org/10.1103/PhysRevB.94.125439

Angaben zu Projekten

Abstract

We present a numerical path-integral iteration scheme for the low-dimensional reduced density matrix of a time-dependent quantum dissipative system. Our approach simultaneously accounts for the combined action of a microscopically modeled pure-dephasing-type coupling to a continuum of harmonic oscillators representing, e.g., phonons, and further environmental interactions inducing non-Hamiltonian dynamics in the inner system represented, e.g., by Lindblad-type dissipation or relaxation. Our formulation of the path-integral method allows for a numerically exact treatment of the coupling to the oscillator modes and moreover is general enough to provide a natural way to include Markovian processes that are sufficiently described by rate equations. We apply this new formalism to a model of a single semiconductor quantum dot which includes the coupling to longitudinal acoustic phonons for two cases: (a) external laser excitation taking into account a phenomenological radiative decay of the excited dot state and (b) a coupling of the quantum dot to a single mode of an optical cavity taking into account cavity photon losses.