Separation of dissipation from diffusion

Abstract

We study velocity correlations induced by diffusion and dissipation in a simple dissipative dynamical system. We observe that diffusion, as a result of time reversible microscopic processes, leads to correlations with different spatial parity from those caused by dissipation, consisting of time irreversible microscopic processes. The velocity correlations observed conflict with the ``molecular chaos'' assumption of the Boltzmann equation. To account for the apparent correlation structures in our simple model system, we propose that they indicate geometric distortion of the phase space.