We prove that the motion of a tagged particle in a one-dimensional fluid of hard point particles in an external potential U may be asymptotically described by a diffusion process. The process is spatially homogeneous or inhomogeneous according to whether U varies on a microscopic or macroscopic scale. The latter process can still be described by a simple Langevin equation, provided that one interprets it in the sense of Stratonovich.
ASJC Scopus subject areas
- Physics and Astronomy(all)