We derive a fluctuation theorem for generalized work distributions, related to bijective mappings of the phase spaces of two physical systems, and use it to derive a two-sided constraint maximum likelihood estimator of their free energy difference which uses samples from the equilibrium configurations of both systems. As an application, we evaluate the chemical potential of a dense Lennard-Jones fluid and study the construction and performance of suitable maps.
@article{arxiv.0809.2256,
title = {Using bijective maps to improve free energy estimates},
author = {A. M. Hahn and H. Then},
journal= {arXiv preprint arXiv:0809.2256},
year = {2009}
}