Does Statistical Mechanics Apply to Driven Steady States of Matter?

R. M. L. Evans
University of Leeds

Complex fluids are easily and reproducibly driven into non-equilibrium steady states by the action of shear flow. Such states are as diverse and interesting as equilibrium states, but are not governed by the same statistics of Boltzmann's law and detailed balance. Under flow, the statistically steady states of, e.g., worm-like micelles are ergodic, and are governed by microscopically reversible laws of motion, as is the case at equilibrium. We can therefore find a non-equilibrium counterpart to the canonical foundations of statistical mechanics, including a principle analogous to detailed balance, with significant consequences for activated processes.