Cold 3-Brane Thermalization, Spacetime Phase Transition, and Primordial Black Holes as Topological Relics.

This paper proposes a unified, non-singular cosmological scenario as an alternative to the inflationary paradigm (ΛCDM). The initial state of the Universe is described as a cold 3-brane (a quantum condensate of spacetime degrees of freedom) embedded in a D-dimensional bulk. The gradual thermalization of the brane due to quantum interactions with the bulk induces a first-order phase transition—a "melting" of the condensate that releases energy into the fields of the Standard Model (Hot Big Bang). Via the Kibble-Zurek mechanism, this transition inevitably traps stable topological defects (gravitational vortices) within the medium, representing primordial black holes equipped with an effective acoustic event horizon.