Cluster Analysis of the Nonlinear Evolution of Large-Scale Structure in an Axion/Gravitino/Photino-Dominated Universe

Abstract
The authors consider nonlinear evolution of the inflationary scale-free spectrum of adiabatic density perturbations in (1) a neutrino-dominated universe (sharp short-wavelength cutoff), and (2) an axion-, gravitino-, or photino-dominated universe (some small-scale power). In (2) galaxy formation begins long before the present (as defined by covariance function), resolving a possible problem in (1). Both models are found to be acceptable upon cluster analysis. The authors believe that a new picture, based on (2), merits consideration.