Nonequilibrium fluctuation theorems in the presence of a time-reversal symmetry-breaking field and nonconservative forces

We study nonequilibrium fluctuation theorems in the presence of a time-reversal symmetry-breaking field and nonconservative forces, in a stochastic as well as a deterministic set up. We consider a system and a heat bath, called the combined system, and show that the fluctuation theorems are valid even when the heat bath goes out of equilibrium during driving. The only requirement for the validity is that, when the driving is switched off, the combined system relaxes to a state having a uniform probability measure on a constant energy surface, consistent with microcanonical ensemble of an isolated system.