High Density Regions from First-Order Phase Transitions

In this chapter we consider dynamics of first-order phase transitions in the early Universe. Numerical results indicate that within a certain range of parameters it leads to formation of separate relatively long-lived clots — configurations filled with a scalar field oscillating around the true vacuum state. Energy is perfectly localized, and density is slightly pulsating around its maximum. This process is accompanied by radiation of scalar waves. Under some conditions the localization of enemy leads to formation of small black holes with high probability.