Inflationary cosmology and large scale structure of the Universe

Abstract

Scale-invariant (flat) fluctuation spectra are the most generic outcomes of inflation. However, current observations of large scale structure require more fluctuation power on large scales than flat spectra give. One such observation concerns the existence of large cosmological bubbles on the scales ˜ (20-50) Mpc in the galaxy distribution. We attempt an explanation of these structures based on an inflationary model containing two scalar fields. One of these fields undergoes a first order phase transition, owing to the evolution of the other. We study the distribution of bubbles formed during the phase trnasition and show that for a wide range of choice of the free parameters in our model, a few bubbles can survive and grow to become the bubble structures observed at present.