Enhanced sampling in numerical path integration: an approximation for the quantum statistical density matrix based on the nonextensive thermostatistics.
Here we examine a proposed approximation for the quantum statistical density matrix motivated by the nonextensive thermostatistics of Tsallis and co-workers. The approximation involves replacing the physical potential energy with an effective one, corresponding to a generalized nonextensive statistical ensemble. We examine the convergence properties of averages calculated using the effective potential, and introduce a related method for enhanced sampling in numerical path integration. As a necessary measure, path integral energy estimators are introduced for potentials that involve explicit temperature dependence. This sampling method is found to be effective for path integral simulations involving broken ergodicity.
Whitfield
T W
TW
Department of Chemistry, Boston University, Boston, Massachusetts 02215, USA.
Straub
J E
JE