Generalized fluctuation relation and effective temperatures in a driven fluid.
By numerical simulation of a Lennard-Jones-like liquid driven by a velocity gradient gamma we test the fluctuation relation (FR) below the (numerical) glass transition temperature T(g) . We show that, in this region, the FR deserves to be generalized introducing a numerical factor X (T, gamma) <1 that defines an "effective temperature" T(FR) =T/X . On the same system we also measure the effective temperature T(eff) , as defined from the generalized fluctuation-dissipation relation, and find a qualitative agreement between the two different nonequilibrium temperatures.
Zamponi
F
F
Dipartimento di Fisica and INFM, Università di Roma La Sapienza, Piazzale Aldo Moro 2, 00185 Roma, Italy.
Ruocco
G
G
Angelani
L
L