Evolution of thick domain walls in inflationary and $p=w\ddot{I}$ universe

Abstract

We study the evolution of thick domain walls in the different models of cosmological inflation, in the matter-dominated and radiation-dominated universe, or more generally in the universe with the equation of state $p=w\ddot{I}$. We have found that the domain wall evolution crucially depends on the time-dependent parameter $C(t)=1/(H(t)\hat{I}{´}_0{)}^2$, where $H(t)$ is the Hubble parameter and $\hat{I}{´}_0$ is the thickness of the wall in flat space-time. For $C(t)>2$ the physical thickness of the wall, $a(t)\hat{I}´(t)$, tends with time to $\hat{I}{´}_0$, which is microscopically small. Otherwise, when $C(t)\le 2$, the wall steadily expands and can grow up to a cosmologically large size.

15 pages, 9 figures