Vierbein walls in condensed matter
PACS: 04.70.Dy, 04.90.+e, 67.57.Fg
The effective field, which plays the part of the vierbein in general relativity, can have topologicaily stable surfaces, vierbein domain walls, where the effective contravariant metric is degenerate. We consider vierbein walls separating domains with the flat space-time which are not causally connected at the classical level. Possibility of the quantum mechanical connection between the domains is discussed.