Research

= Nonequilibrium Statistical Mechanics =

The first law of thermodynamics states that energy can flow into a system both as heat and work. The second law states that heat divided by temperature is a particularly pernicious quantity. It represents an increase in something like a debt which can never be bought down, only exported somewhere else.

Recent discoveries in nonequilibrium statistical mechanics have centered around the microscopic origins of this 'irreversibility.' We have uncovered surprising new connections to observable information. For example, energy rejected from a process, but not used to do work, has to be counted as heat. The more statistical information we have about a process, the more avenues we have to extract some of that energy, shifting it under the heading of 'work.'

We are investigating these microscopic processes through simulations on nanoscale energy conversion devices.

= Local Free Energy Methods =

Molecule partitioning underlies drug activity, separation and extraction, and solid/liquid phase stability. A variety of factors come together to determine the part of a solution that a molecule will take up residence, and more than one explanation is possible. The most useful of these for designing new molecular and solvent structures is a local picture, where a free energy for moving a molecule to different points in solution acts like a voltage probe in an electric circuit. The energy required for moving a molecule to any point in solution can be divided into molecular packing, direct energetic interaction with a surrounding set of ligands, and long-range solvent polarization terms. We are building models for these components that will greatly simplify the process of designing better devices using molecular information.