Nonequilibrium fluxes in steady state: connection with boundary conditions

A characteristic feature of nonequilibrium steady states is their ability to maintain nonzero fluxes in steady state. Here I will discuss mass fluxes in a class of nonequilibrium systems characterized by driving at the level of individual particles. By constructing an explicit mathematical representation of the full nonequilibrium steady state, I am able to quantitatively connect mass fluxes in the bulk with the boundary conditions. In particular, the emergence of nonzero mass fluxes is tied to the breaking of detailed balance at the boundaries.