Evolution of thick domain walls in inflationary and $$p=w\rho $$ p=wρ universe

Abstract

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 $$p=w\rho $$ p=wρ . We have found that the domain wall evolution crucially depends on the time-dependent parameter $$C(t)=1/(H(t)\delta _0)^2$$ C(t)=1/(H(t)δ0)2 , where H(t) is the Hubble parameter and $$\delta _0$$ δ0 is the thickness of the wall in flat space-time. For $$C(t)>2$$ C(t)>2 the physical thickness of the wall, $$a(t)\delta (t)$$ a(t)δ(t) , tends with time to $$\delta _0$$ δ0 , which is microscopically small. Otherwise, when $$C(t) \le 2$$ C(t)≤2 , the wall steadily expands and can grow up to a cosmologically large size.