Hubble Tension versus the Cosmic Evolution of Hubble Parameter in the Unicentric Model of the Observable Universe

Abstract

Recently, a unicentric model of the observable universe (UNIMOUN) was proposed. Accordingly, big bangs are common events in our infinitely large, flat, homogeneous and isotropic parent universe. Their progenitors are clusters of cosmically dead and massive neutron stars that merged after reaching the ultimate lowest quantum energy state, where the matter is in an incompressible superconducting gluon-quark superfluid state and zero-entropy, hence granting the resulting progenitors measurable sizes and immunity to collapsing into black holes. Our big bang happened to occur in our neighbourhood, thereby enduing the universe, the observed homogeneity and isotropy. As the enclosed mass of the progenitor was finite, the dynamically expanding curved spacetimes embedded the fireball started flattening to finally diffuse into the flat spacetime of the parent universe. By means of general relativistic numerical hydrodynamical calculations, we use the H -metric to follow the time-evolution of the spacetime embedding the progenitor during the hadronization and the immediately following epochs. Based thereon, we find that the kinetic energy of newly created normal matter increases with distance in a self-similar manner, imitating thereby outflows of nearly non-interacting particles. On cosmic time scales, this behaviour yields a Hubble parameter, H ( t ), which decreases slowly with the distance from the big bang event. Given the sensitivity of the data of the Cosmic Microwave Background (CMB) from Planck to the underlying cosmological model, we conclude that UNIMOUN is a viable alternative to ΛCMD-cosmologies.