Coherently perturbed Milne Universe

The present paper deals with the formulation of Einstein–Gordon equations for Friedmann–Robertson–Walker (FRW) geometries, in feedback reaction with the quartically self-interacting physical field, arisen from the “inner parity” spontaneous breaking. The Hamiltonian density non-positive extrema would classically forbid both spatially closed and flat homogeneous and isotropic worlds, if these allow the physical field to (repeatedly) go through and to settle down in a ground state. It turns out that the fixed point exact solutions of the spontaneous Z2-symmetry breaking Einstein–Gordon equations are describing either anti-de Sitter or Milne Universes. The latter is consistent with the recent gravity lensing and supernova data, which have confirmed the hypothesis of an Universe dominated by dark energy, whose nature is completely unknown at present. Finally, by taking the electroweak symmetry scale to be the Z2-invariance breaking one, we speculate on the cosmological implications of the Higgs–anti-de Sitter bubbles.