Nonequilibrium fluctuations in a resistor

Nicolas Garnier (1) , Sergio Ciliberto (1)

1 Phys-ENS - Laboratoire de Physique de l'ENS Lyon

In small systems where relevant energies are comparable to thermal agitation, fluctuations are of the order of average values. In systems in thermodynamical equilibrium, the variance of these fluctuations can be related to the dissipation constant in the system, exploiting the Fluctuation-Dissipation Theorem (FDT). In non-equilibrium steady systems, Fluctuations Theorems (FT) additionally describe symmetry properties of the probability density functions (PDFs) of the fluctuations of injected and dissipated energies. We experimentally probe a model system: an electrical dipole driven out of equilibrium by a small constant current $I$, and show that FT are experimentally accessible and valid. Furthermore, we stress that FT can be used to measure the dissipated power $\bar{\cal P}=RI^2$ in the system by just studying the PDFs symmetries.

Mots clés: Out of equilibrium; Fluctuation theorem; Langevin dynamics

Domaines: Mécanique statistique [cond-mat.stat-mech]

Nicolas Garnier, Sergio Ciliberto. Nonequilibrium fluctuations in a resistor. Physical Review E : Statistical, Nonlinear, and Soft Matter Physics, 2005, 71 (060101), pp.4. ⟨ensl-00180072⟩