Regensburg 2002 – wissenschaftliches Programm
DY 46.10: Poster
Donnerstag, 14. März 2002, 15:30–18:00, D
Coherent state path integral approach to dissipative quantum dynamics. — •Alexey Novikov1,2, Ulrich Kleinekathöfer1,2, and Michael Schreiber1,2 — 1Institut für Physik, Technische Universität, D-09107 Chemnitz, Germany — 2International University Bremen, D-28725 Bremen
Employing the path integral technique the quantum
dynamics of systems with dissipation is investigated. The dissipation in
the system is described as a consequence of its coupling to a reservoir
consisting of an infinite or an finite number of harmonic oscillators.
calculated the matrix elements of operator of evolution using
path integrals in coherent state representation.
In contrast to the well-known Herman-Kluk method which is usually used together with a phase space representation in the present alternative treatment we use only a coherent state basis.
This approach can be used for system Hamiltonians which are given in a harmonic oscillator eigenstate representation. The system-bath coupling is assumed to be bilinear. We calculated the path integral in stationary-phase approximation, which leads to exact results for a system of coupled harmonic oscillators. In order to solve the equation of motion we diagonalized the Lagrangian, which can be reduced to a Lagrangian of a number of independent oscillators by this diagonalization.
Using this treatment we consider quantum damped harmonic oscillator within and without the rotating-wave approximation. The matrix elements of density operator has been calculated. We evaluated the relaxation in the system at non-equilibrium initial condition.