Interaction of domain walls with scalar particles in the early Universe

The formation of solitons (such as closed domain walls) in the super-Early Universe is predicted in a number of theories of the formation of primordial black holes. However, the interaction of particles of the surrounding medium with the solitons should affect their dynamics. In the paper, we consider the interaction between domain walls and scalar particles which can play a role of dark matter. It is shown that when the temperature of the scalar particle gas, caused by the expansion of the Universe, decreases below a certain threshold value, the wall abruptly becomes opaque and locks particles inside itself. We discuss the dynamics of a single domain wall taking into account pressure of scalar particles locked inside a closed wall. It is shown, this effect leads to a time delay of domain wall collapse and the deferred formation of primordial black holes.