Theory of Many Body Processes in Chemical Physics

比尔·莱因哈特（Bill Reinhardt）获得了理论与计算化学计划的资助，研究化学物理中的多体过程。这项工作的主要部分是针对凝聚相模拟，重点是采样改进和熵和自由能差的控制计算。随着方法的发展，它将被嵌入到广泛的仿真软件包中。第二个努力涉及玻色-爱因斯坦凝聚体的大振幅动力学。这项工作将涉及利用非线性薛定谔方程，对吸引和排斥凝聚体的多维暗孤子进行半经典建模。自由能和自由能差的知识在化学和生物物理化学中是至关重要的，然而，对其有效计算的进展缓慢。允许快速自由能计算的算法发展将对蛋白质折叠和酶-底物结合的理论模拟产生重大影响。最近玻色凝聚的实验实现为宏观量子系统的行为打开了一扇新窗口，这反过来又激发了对这一现象的理论基础的新努力。

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.