Abstract
The principle of detailed balance puts a number of constraints on the stochastic dynamics of any system that is ergodic, microscopically reversible, and in an equilibrium state. If work is done to drive such a system out of equilibrium, it will, in many cases, remain ergodic, microscopically reversible, and in a statistically steady (albeit non-equilibrium) state. By studying how such conditions give rise to the constraints of detailed balance at equilibrium, we can apply the same principles to derive a non-equilibrium counterpart to detailed balance, applicable to a wide sub-class of driven steady states, and investigate the consequences for activated processes.