Non Poissonian statistics in a low density fluid

P. Visco 1, 2, F. van Wijland 1, 3, E. Trizac 1

The Journal of Physical Chemistry B 112, 17 (2008) 5412

Our interest goes to the collisional statistics in an arbitrary interacting fluid. We show that even in the low density limit and contrary to naive expectation, the number of collisions experienced by a tagged particle in a given time does not obey Poisson law, and that conversely, the free flight time distribution is not a simple exponential. As an illustration, the hard sphere fluid case is worked out in detail. For this model, we quantify analytically those deviations and successfully compare our predictions against molecular dynamics simulations.

  • 1. Laboratoire de Physique Théorique d'Orsay (LPT),
    CNRS : UMR8627 – Université Paris XI - Paris Sud
  • 2. Laboratoire de Physique Théorique et Modèles Statistiques (LPTMS),
    CNRS : UMR8626 – Université Paris XI - Paris Sud
  • 3. Matière et Systèmes Complexes (MSC),
    CNRS : UMR7057 – Université Paris VII - Paris Diderot