Adel Awad, Zewail U. (Egypt)

Non-singular Cosmologies and Fixed Points

In a FRW universe, we show that a general barotropic one-component fluid is described by a solution which has no future finite-time singularities if the equation of state allows for one future fixed point for the first-order system governing the Hubble parameter. If we have in addition a past fixed point, this solution is completely non-singular and interpolates monotonically between spaces with positive or vanishing cosmological constants. In this general framework it is impossible for the universe to evolve from a region in which $w>-1$ to another with $w<-1$, (i.e., a phantom region) in a finite time. In this framework we study the general case of viscous cosmic fluid and find exact solutions which serves as unified dark fluid models and a non-singular phantom dark energy solution.

Aug 28 at 4pm in Geo/Phys Room 407