Abstract
The linear response in different models of driven granular gases is studied. In some situations, even if the the velocity statistics can be strongly non-Gaussian, appreciable violations of the Einstein formula for diffusion versus mobility cannot be observed. The situation changes when correlations between different degrees of freedom are present: in this case, although a form of fluctuation-dissipation relation holds, the differential velocity response of a particle and its velocity self-correlation are no more proportional. This happens at high densities, strong inelasticities, or weak efficiency of the external driving, but still in the fluid-like (and ergodic) regime.
Users
Please
log in to take part in the discussion (add own reviews or comments).