# Field induced stationary state for an accelerated tracer in a bath

### Matthieu Barbier ^{1}, Emmanuel Trizac ^{1}

#### Journal of Statistical Physics **149** (2012) 317-341

Our interest goes to the behavior of a tracer particle, accelerated by a constant and uniform external field, when the energy injected by the field is redistributed through collision to a bath of unaccelerated particles. A non equilibrium steady state is thereby reached. Solutions of a generalized Boltzmann-Lorentz equation are analyzed analytically, in a versatile framework that embeds the majority of tracer-bath interactions discussed in the literature. These results --mostly derived for a one dimensional system-- are successfully confronted to those of three independent numerical simulation methods: a direct iterative solution, Gillespie algorithm, and the Direct Simulation Monte Carlo technique. We work out the diffusion properties as well as the velocity tails: large v, and either large -v, or v in the vicinity of its lower cutoff whenever the velocity distribution is bounded from below. Particular emphasis is put on the cold bath limit, with scatterers at rest, which plays a special role in our model.

- 1. Laboratoire de Physique Théorique et Modèles Statistiques (LPTMS),

CNRS : UMR8626 – Université Paris XI - Paris Sud