Domain Walls of Low Tension in Cosmology

Abstract: In the present article we put up for discussion the idea of there existing several versions, phases, of the vacuum, in the spirit in which we have long worked on this idea, namely the Multiple Point Criticality Principle, which also says that these different vacuum phases have the same energy density. We mention that we indeed predicted the Higgs mass to be 135 plus minus 10 GeV, which when measured turned out to be 125 GeV, using the assumption of this Multiple Point Criticality Principle. We consider the possibility that there is one type of vacuum in the galaxy clusters (the usual vacuum) and another type of vacuum in the voids. The hope that there could indeed be such a low tension S of the domain wall between these two phases, that it would not totally upset cosmology is based on our dark matter model. In this model dark matter consists of pearls or bubbles of a new vacuum phase, with ordinary matter inside it under very high pressure. The order of magnitude of cubic root S of order MeV or 100 MeV could make such domain walls astronomically viable. We successfully estimate the order of magnitude of the variations in the fine structure constant in different places astronomically, but the similar variations in proton mass over electron mass should have been much bigger than seen experimentally in our model. The Universe s surprisingly early galaxies seen by JWST, James Webb telescope, may agree well with our model. Replacing the usual cosmological constant by domain walls in the standard cosmological model would lead to a cubic root of the tension being cubic root of S of order 30 MeV.