On the efficiency of path sampling methods for the calculation of free energies from non-equilibrium simulations

According to the Jarzynski theorem, equilibrium free energy differences can be calculated from the statistics of work carried out during nonequilibrium transformations. Although exact, this approach can be plagued with large statistical errors, particularly for systems driven strongly away from equilibrium. Recently, several approaches have been suggested for reducing these errors. In this paper we study the efficiency of these methods using two models for which analytical solutions exist.