Regensburg 2004 – wissenschaftliches Programm
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DY: Dynamik und Statistische Physik
DY 46: Poster
DY 46.45: Poster
Donnerstag, 11. März 2004, 16:00–18:00, Poster D
Non-Markovian density matrix theories based on the decomposition of the spectral density — •U. Kleinekathöfer1,2 and M. Schreiber2 — 1International University Bremen, 28725 Bremen, Germany — 2Institut für Physik, Technische Universität Chemnitz, 09107 Chemnitz
For the description of dynamical effects in quantum mechanical systems on ultra-short time scales memory effects play an important role. Here we propose two different theories [1] which are either based on the time-convolution Nakajima-Zwanzig projection operator formalism or the time-convolutionless Hashitsume approach. The proposed theories as well as the method by Meier and Tannor [2] are based on a numerical decomposition of the spectral density. For the example of the damped harmonic oscillator these non-Markovian theories are compared among each other, to Markovian approaches neglecting the memory effect and to path integral calculations. Some of the proposed non-Markovian theories treat explicitly time-dependent system Hamiltonians nonperturbatively. Therefore these method can be used for the description of experiments with arbitrary large laser fields.
[1] U. Kleinekathöfer, J. Chem. Phys. (submitted).
[2] C. Meier and D.J. Tannor, J. Chem. Phys. 111, 3365 (1999).