Effective temperatures of a heated Brownian particle
LPMCN, Université de Lyon; UMR 5586 Université Lyon 1 and CNRS - F-69622 Villeurbanne, France, EU
2 LIPHY, Université Joseph Fourier - Grenoble 1; UMR 5588 Université Grenoble 1 and CNRS F-38402 Saint Martin d'Hères, France, EU
Accepted: 20 April 2011
We investigate various possible definitions of an effective temperature for a particularly simple nonequilibrium stationary system, namely a heated Brownian particle suspended in a fluid. The effective temperature based on the fluctuation dissipation ratio depends on the time scale under consideration, so that a simple Langevin description of the heated particle is not possible on short time scales. The short- and long-time limits of this effective temperature are shown to be consistent with the temperatures estimated from the kinetic energy and Einstein relation, respectively. The transient fluctuation theorem provides still another definition of the temperature, which is shown to coincide with the short-time value of the fluctuation dissipation ratio.
PACS: 05.70.Ln – Nonequilibrium and irreversible thermodynamics / 05.40.-a – Fluctuation phenomena, random processes, noise, and Brownian motion / 47.11.Mn – Molecular dynamics methods
© EPLA, 2011