Tagged particle diffusion in one dimensional systems with Hamiltonian dynamics
Anjan Roy (ICTS, Bangalore, India)

Observing the dynamics of a single tagged particle in a many particle system constitute a simple way of probing the complex dynamics of an interacting many body system. We present our results on tagged particle diffusion in a one-dimensional gas of classical point particles evolving under Hamiltonian dynamics between fixed and periodic walls. Systems studied include equal and alternate mass hard particle gas, the harmonic chain and anharmonic chains such as Fermi-Pasta-Ulam and Lennard-Jones chains. We have studied both short time regime when the effect of boundary is not felt and the tagged particle behaves as if in an infinite system, as well as long time regime when the boundary effect comes into play.