1. Forward-backward semiclassical initial value series representation of quantum correlation functions.
- Author
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Martin-Fierro, Eva and Pollak, Eli
- Subjects
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QUANTUM perturbations , *APPROXIMATION theory , *STATISTICAL correlation , *PHASE space , *BOSONS , *DEGREES of freedom , *MATRIX mechanics - Abstract
The forward-backward (FB) approximation as applied to semiclassical initial value representations (SCIVR’s) has enabled the practical application of the SCIVR methodology to systems with many degrees of freedom. However, to date a systematic representation of the exact quantum dynamics in terms of the FB-SCIVR has proven elusive. In this paper, we provide a new derivation of a forward-backward phase space SCIVR expression (FBPS-SCIVR) derived previously by Thompson and Makri [Phys. Rev. E 59, R4729 (1999)]. This enables us to represent quantum correlation functions exactly in terms of a series whose leading order term is the FBPS-SCIVR expression. Numerical examples for systems with over 50 degrees of freedom are presented for the spin boson problem. Comparison of the FBPS-SCIVR with the numerically exact results of Wang [J. Chem. Phys. 113, 9948 (2000)] obtained using a multiconfigurational time dependent method shows that the leading order FBPS-SCIVR term already provides an excellent approximation. [ABSTRACT FROM AUTHOR]
- Published
- 2006
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