Bill Reinhardt is supported by a grant from the Theoretical and Computational Chemistry Program to study many-body processes in chemical physics. The major portion of this effort is aimed at condensed-phase simulations, with emphasis on sampling improvement and the controlled calculation of entropy and free-energy differences. As the methodology is developed, it will be embedded into widespread simulation packages. A secondary effort concerns large amplitude dynamics in Bose-Einstein condensates. This work will involve semiclassical modeling of dark solitons in multiple dimensions for both attractive and repulsive condensates, employing the nonlinear Schrodinger equation. Knowledge of free energies and free energy differences are of central importance in chemistry and biophysical chemistry, yet progress toward their efficient computation has been slow. Algorithmic developments that allow for rapid free energy computations will have a major impact on theoretical simulations of protein folding and enzyme-substrate binding. The recent experimental realization of Bose condensation opens a new window into the behavior of macroscopic quantum systems, which in turn inspires new efforts into theoretical underpinnings of this phenomenon.
