Challenges in Non-Linear Gravitational Clustering
Abstract
This article addresses some issues related to statistical description of gravitating systems in an expanding backgrounds. In particular, I describe (a) how the non linear mode-mode coupling transfers power from one scale to another in the Fourier space if the initial power spectrum is sharply peaked at a given scale and (b) what are the asymptotic characteristics of gravitational clustering that are independent of the initial conditions. The analysis uses a new approach based on an integro-differential equation for the evolution of the gravitational potential in the Fourier space. I show how this equation allows one to understand several aspects of nonlinear gravitational clustering and provides insight in to the transfer of power from one scale to another through nonlinear mode coupling. Numerical simulations as well as analytic work shows that power transfer leads to a universal power spectrum at late times, somewhat reminiscent of the existence of Kolmogorov spectrum in fluid turbulence.
Cite
@article{arxiv.astro-ph/0512077,
title = {Challenges in Non-Linear Gravitational Clustering},
author = {T. Padmanabhan},
journal= {arXiv preprint arXiv:astro-ph/0512077},
year = {2009}
}
Comments
Based on the lectures given at (i)UCT Meeting on Cosmology, 6-10 July,05; (ii)Meeting on `Statistical Mechanics of Non-Extensive Systems', 24-25 Oct 05, Paris. To be published in a Special Issue of Les Comptes rendus de l'Academie des Sciences. 15 pages; 4 figures