Evolution of thick domain walls in inflationary and $$p=who $$ p = w ρ universe

摘要

We study the evolution of thick domain walls in the inflationary universewith quadratic inflaton potential $m^2Phi^2/2$, as well as in thematter-dominated and radiation-dominated universe, or more generally in theuniverse with the equation of state $p=who$. We have found that the domainwall evolution crucially depends on the time-dependent parameter$C(t)=1/(H(t)delta_0)^2$, where $H(t)$ is the Hubble parameter and $delta_0$is the width of the wall in flat space-time. For $C(t)>2$ the physical width ofthe wall, $a(t)delta(t)$, tends with time to constant value $delta_0$, whichis microscopically small. Otherwise, when $C(t) leq 2$, the wall steadilyexpands and can grow up to a cosmologically large size.