Transition to irreversibility in sheared suspensions

The transition to irreversibility observed in experiments with suspensions of non-Brownian particles subjected to an oscillatory shear flow is explained by using the Gibbs entropy and the second law of thermodynamics. We show that the origin of the transition to irreversibility is the coupling between diffusion and inertial forces associated to the existence of a velocity gradient in the system. This coupling is characterizad by an Onsager coefficient and is responsible for the breakdown of the fluctuation-dissipation theorem. Using lattice Boltzmann simulations we characterize the transition through the power spectra of particle trajectories.