  We investigate the correspondence between a non-equilibrium ensemble defined
via the distribution of phase-space paths of a Hamiltonian system, and a system
driven into a steady-state by non-equilibrium boundary conditions. To discover
whether the non-equilibrium path ensemble adequately describes the physics of a
driven system, we measure transition rates in a simple one-dimensional model of
rotors with Newtonian dynamics and purely conservative interactions. We compare
those rates with known properties of the non-equilibrium path ensemble. In
doing so, we establish effective protocols for the analysis of transition rates
in non-equilibrium quasi-steady states. Transition rates between potential
wells and also between phase-space elements are studied, and found to exhibit
distinct properties, the more coarse-grained potential wells being effectively
further from equilibrium. In all cases the results from the boundary-driven
system are close to the path-ensemble predictions, but the question of
equivalence of the two remains open.
