Real versus Complex Fermion Bare Mass and Multi-Wall String Defect Annihilation
The paper proposes a mechanism to annihilate cosmological domain walls (DWs) arising from a global U(1) symmetry breaking, which is usually cosmologically problematic. The authors show that introducing a small bare mass term for fermions coupled to the symmetry-breaking scalar generates a temperature-dependent vacuum bias through radiative corrections. This bias drives the DW collapse and complete annihilation, resolving the cosmological DW problem.