Illustration of the Jarzynski nonequilibrium work relation for an ideal   gas
  The Jarzynski relation is a recently discovered result relating the average exponential of the work done under nonequilibrium conditions to an equilibrium free energy difference. We illustrate this remarkable relation by considering the expansion and compression of a classical ideal gas particle inside a cavity with a moving piston in one dimension. Using a simple relationship between the distributions of the nonequilibrium work done in the two (forward and reverse) processes, we verify the Jarzynski relation and discuss the practical realization of the Jarzynski equality for the model. 
Rhonald C. Lua