||Annu. Rev. Astron. Astrophys. 1991. 29:
Copyright © 1991 by Annual Reviews. All rights
2.2.4. DOMAIN WALLS
The GUTs phase transition produces certain characteristic
discontinuities in the matter distribution. This happens during the
spontaneous breakdown of symmetry, which leads the mediating scalar
fields to have a discrete set of characteristic values. Thus one
region or ``domain'' has one value of the scalar field, while its
neighbor has another.
The boundary wall between the domains would therefore be a region of
discontinuity. We expect to see this as a sheet of inhomogeneity in
the large scale matter distribution in the universe. The present data
do not reveal any such inhomogeneity in the observable universe.