Convergence and path cancellation in quantum Monte Carlo real time path integration

Journal Article · Fri Nov 01 00:00:00 EST 1996 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.472547· OSTI ID:388172

Gentile, A C; Evensky, D A; Durant, J L ^[1]; Brown, N J ^[2]; Koszykowski, M L ^[1]

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1. Sandia National Laboratories, Livermore, California 94551 (United States)
2. Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720 (United States)

We find that poor resolution of the tails of the distribution of integrands obtained inhibits convergence in Monte Carlo calculation of real time path integrals. We show that many methods previously tried to improve convergence neither resolve nor diminish the tails effectively. We find that large contributions to the integrand come from paths that have a large variance from the zero-path and/or that have few zero crossings. The results of crude dampings based on where such paths are poorly sampled suggest that exploring cancellations of paths characterized by path variance and zero crossings may be effective in improving convergence. {copyright} {ital 1996 American Institute of Physics.}

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 388172
• Journal Information: Journal of Chemical Physics, Vol. 105, Issue 17; Other Information: PBD: Nov 1996
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
40 CHEMISTRY
REAL TIME SYSTEMS
MONTE CARLO METHOD
CHEMICAL REACTION KINETICS
CORRELATION FUNCTIONS
QUANTUM CHEMISTRY
AUTOCORRELATIONS