Experimental verification of a modified fluctuation-dissipation relation for a micron-sized particle in a non-equilibrium steady state

Juan Ruben Gomez-Solano (1) , Artyom Petrosyan (1) , Sergio Ciliberto (1) , Raphael Chetrite (1) , Krzysztof Gawedzki (1)

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

A modified fluctuation-dissipation-theorem (MFDT) for a non-equilibrium steady state (NESS) is experimentally checked by studying the position fluctuations of a colloidal particle whose motion is confined in a toroidal optical trap. The NESS is generated by means of a rotating laser beam which exerts on the particle a sinusoidal conservative force plus a constant non-conservative one. The MFDT is shown to be perfectly verified by the experimental data. It can be interpreted as an equilibrium-like fluctuation-dissipation relation in the Lagrangian frame of the mean local velocity of the particle.

Keywords: Non-equilibrium steady state; fluctuation-dissipation relations; Langevin dynamics

Domains: Physics [physics]; Condensed Matter [cond-mat]; Statistical Mechanics [cond-mat.stat-mech]

Juan Ruben Gomez-Solano, Artyom Petrosyan, Sergio Ciliberto, Raphael Chetrite, Krzysztof Gawedzki. Experimental verification of a modified fluctuation-dissipation relation for a micron-sized particle in a non-equilibrium steady state. Physical Review Letters, 2009, 103 (4), pp.040601. ⟨10.1103/PhysRevLett.103.040601⟩. ⟨ensl-00365952v3⟩