HAL : in2p3-00282359, version 1
 arXiv : 0805.1360
 DOI : 10.1063/1.2839124
 Dynamics and Thermodynamics of systems with long range interactions: theory and experiments, Assisi : Italie (2007)
 Infinite self-gravitating systems and cosmological structure formation
 (2008)
 The usual thermodynamic limit for systems of classical self-gravitating point particles becomes well defined, as a {\it dynamical} problem, using a simple physical prescription for the calculation of the force, equivalent to the so-called Jeans' swindle''. The relation of the resulting intrinsically out of equilibrium problem, of particles evolving from prescribed uniform initial conditions in an infinite space, to the one studied in current cosmological models (in an expanding universe) is explained. We then describe results of a numerical study of the dynamical evolution of such a system, starting from a simple class of infinite shuffled lattice'' initial conditions. The clustering, which develops in time starting from scales around the grid scale, is qualitatively very similar to that seen in cosmological simulations, which begin from lattices with applied correlated displacements and incorporate an expanding spatial background. From very soon after the formation of the first non-linear structures, a spatio-temporal scaling relation describes well the evolution of the two-point correlations. At larger times the dynamics of these correlations converges to what is termed self-similar'' evolution in cosmology, in which the time dependence in the scaling relation is specified entirely by that of the linearized fluid theory. We show how this statistical mechanical toy model'' can be useful in addressing various questions about these systems which are relevant in cosmology. Some of these questions are closely analagous to those currently studied in the literature on long range interactions, notably the relation of the evolution of the particle system to that in the Vlasov limit and the nature of approximately quasi-stationary states.
 Thème(s) : Physique/Astrophysique/Cosmologie et astrophysique extra-galactiquePhysique/Matière Condensée/Mécanique statistiquePhysique/Relativité Générale et Cosmologie QuantiquePlanète et Univers/Astrophysique
 Lien vers le texte intégral : http://fr.arXiv.org/abs/0805.1360
 in2p3-00282359, version 1 http://hal.in2p3.fr/in2p3-00282359 oai:hal.in2p3.fr:in2p3-00282359 Contributeur : Swarna Bassava <> Soumis le : Mardi 27 Mai 2008, 13:24:28 Dernière modification le : Jeudi 12 Juin 2008, 17:07:38