A fundamental question in systems driven out of thermodynamic equilibrium is how the properties of the Non Equilibrium Stationary States (NESS) are related to the specific mechanisms by which external energy is supplied.
In this talk, i will introduce granular materials in the context of non equilibrium statistical mechanics. I will focus on experimental and numerical results about the occurrence of non monotonic energy transfer to a driven dense granular system [1]. This counter intuitive effect can be understood by frictional effects and i will present an analytically solvable model that well reproduces the observed phenomenology, illustrating the role of the competing effects of forcing and dissipation.
[1]: Plati et al. Phys. Rev. Research 3, 013011