Generation of primordial cosmological perturbations from statistical mechanical models

The initial conditions describing seed fluctuations for the formation of structure in standard cosmological models, i.e. the Harrison-Zeldovich distribution, have very characteristic “super-homogeneous” properties: they are statistically translation invariant and isotropic, and the variance of the mass fluctuations in a region of volume V grows more slowly than V. We discuss the geometrical construction of distributions of points in ${\mathbf{R}}^3$ with similar properties encountered in tiling and in statistical physics, e.g. the Gibbs distribution of a one-component system of charged particles in a uniform background [one-component plasma (OCP)]. Modifications of the OCP can produce equilibrium correlations of the kind assumed in the cosmological context. We then describe how such systems can be used for the generation of initial conditions in gravitational N-body simulations.