2007

Abstract:

Molecular Dynamics is a method for simulating materials at microscopic length and time scales.  Often we are happy to resolve atomic length scales, but would rather not resolve such fine time scales. Indeed, the time step-length used in MD is typically restricted by the smallest time scale in the system.  This makes long- time simulation, of the type necessary to observe grain-boundary motion (for example), unfeasible. I will present a general framework for overcoming this difficulty while still maintaining detailed microscopic information about the system. The strategy is to coarse- grain the system in time:  this leads to a time-averaged density field, for which we can derive approximate equations of motion.  The motion of this field is described by a non-local partial differential equation which no longer contains the undesired time-scales of the original system.