  The Jarzynski equality is one of the most influential results in the field of
non equilibrium statistical mechanics. This celebrated equality allows to
calculate equilibrium free energy differences from work distributions of
nonequilibrium processes. In practice, such calculations often suffer from poor
convergence due to the need to sample rare events. Here we examine if the
inclusion of measurement and feedback can improve the convergence of
nonequilibrium free energy calculations. A modified version of the Jarzynski
equality in which realizations with a given outcome are kept, while others are
discarded, is used. We find that discarding realizations with unwanted outcomes
can result in improved convergence compared to calculations based on the
Jarzynski equality. We argue that the observed improved convergence is closely
related to Bennett's acceptance ratio method, which was developed without any
reference to measurements or feedback.
