THE DOMAIN-WALL NETWORK OF EXPLICITLY BROKEN O(N) MODEL

Domain walls joined together by cosmic strings are formed due to breaking of an approximate symmetry. Using a typical model with an approximate global O(N) symmetry, we study the evolution of the domain wall network that has many types of strings. The two-dimensional simulations show that in the system, unlike the domain wall network with one type of strings such as invisible axion, pair annihilation of strings does not occur so frequently. As a result, domain walls can make the cellular structure inside the cosmological horizon of the universe, though the walls do not stand still. The domain wall network of this type suggests that there is a possibility that domain walls induce the formation of the large scale structure of the universe.