Ernst, M. H.Brito López, Ricardo2023-06-202023-06-201998-09-010295-507510.1209/epl/i1998-00388-9https://hdl.handle.net/20.500.14352/58494© EDP Sciences. It is a pleasure to thank D. Frenkel for an invaluable comment and helpful correspondence. We thank T. P. C. van Noije, J. A. G. Orza, I. Pagonabarraga and M. Hagen for stimulating discussions. The authors also acknowledge financial support from the Offces of International Relations of Universidad Complutense and Universiteit Utrecht. One of us (RB) acknowledges support to DGICYT (Spain) number PB94-0265.The total energy E(t) in a fluid of inelastic particles is dissipated through inelastic collisions. When such systems are prepared in a homogeneous initial state and evolve undriven, E(t) decays initially as t^(−2) ~ exp[−2ετ ] (known as Haff's law), where “τ” is the average number of collisions suffered by a particle within time t, and ε = 1−α2 measures the degree of inelasticity, with α the coefficient of normal restitution. This decay law is extended for large times to E(t) ~ τ^(−d/2) in d dimensions, far into the nonlinear clustering regime. The theoretical predictions are quantitatively confirmed by computer simulations, and hold for small to moderate inelasticities with 0.6 < α < 1.engjournal articlehttp://iopscience.iop.org/0295-5075/43/5/497/pdf/0295-5075_43_5_497.pdfhttp://iopscience.iop.org/http://arxiv.org/open access536Statistical MechanicsKinetic TheoryPorous MaterialsGranular MaterialsTermodinámica2213 Termodinámica