Erasure of Defects:

Topological defects–such as Domain Walls cosmic strings and magnetic monopoles–are expected to appear during a phase transition in the GUT of particle physics. Such monopoles would be the universe''s dominant matter during the early universe. However this is in tension with the fact that monopoles have not been observed. The former is known as the cosmological monopole problem. Different solutions to this problem are known today with inflation being the most well-known. In this scenario the universe inflates dilutes the monopoles and their density decreases to acceptable levels. Another solution was proposed by Dvali Liu and Vachaspati in 1997.The main idea is that Domain Walls generated during the same phase transition swept away the monopoles before decaying.In general this solution proposes that defect interactions lead to a defect erasure mechanism. This mechanism has been investigated in a SU(5) grand unified model.