Energy distribution and effective temperatures in a driven dissipative model

We investigate nonequilibrium behavior of driven dissipative systems, using a model we recently presented Phys. Rev. Lett. 93 240601 (2004)]. We solve the non-Boltzmann steady state energy distribution and the temporal evolution to it, and find its high energy tail to behave exponentially. We demonstrate that various measures of effective temperatures generally differ. We discuss infinite hierarchies of effective temperatures defined from moments of the nonexponential energy distribution, and relate them to the “configurational temperature,” measured directly from instantaneous particle locations without any kinetic information. We calculate the “granular temperature,” characterizing the average energy in the system, two different “fluctuation temperatures,” scaling fluctuation-dissipation relations, and the “entropic temperature,” defined from differentiating the entropy with respect to energy.