On the relaxation rate of short chains of rotors interacting with langevin thermostats

Abstract

In this short note, we consider a system of two rotors, one of which interacts with a Langevin heat bath. We show that the system relaxes to its invariant measure (steady state) no faster than a stretched exponential exp(−ct1/2). This indicates that the exponent 1/2 obtained earlier by the present authors and J.-P. Eckmann for short chains of rotors is optimal.