Phase transitions during Cyclic-Inflation and Non-gaussianity

Abstract

Typically cold inflation with positive vacuum energy density dilutes all matter except the quan- tum fluctuations which are stretched outside the Hubble patch during inflation. However the cyclic- inflation scenario, where the universe undergoes many many asymmetric cycles leading to an overall exponential growth, operates in the presence of thermal matter. Thus, while some of the nice prop- erties of cold inflation is preserved, in cyclic inflationary models thermal excitations are continually produced and there exists a unique opportunity of imprinting interesting thermal history in CMBR. In particular, we will see that a phase transition can lead to observably large higher order nongaus- sianities as the critical temperature is approached, and that these are increasingly divergent with the order of the correlations.

8 pages, 8 figures