Cosmological Expansion with Global Phase Normalization by the Hubble Horizon

Abstract

We argue that cosmological expansion is subject to a global phase normalization in the gravitational path integral, fixed by causal horizon boundary conditions rather than by local dynamics. In this formulation, the cosmological conformal factor is not a propagating degree of freedom but a global gauge variable fixed by the Hamiltonian constraint, rendering the conventional conformal-factor problem inapplicable. A de Sitter turning point $(q=-1)$ uniquely fixes the phase density $\Lambda =J$ as the leading order integrating factor when the horizon Clausius relation holds, where $J$ is the trace of the Schouten tensor of the cosmological background. We parameterize departures from equilibrium by a single variance parameter $\beta$ governing non-adiabatic background evolution over a Hubble time scale. The resulting Hubble expansion points to a phantom regime beyond $\Lambda$CDM without new degrees of freedom. It provides a natural origin for cosmological tensions expressed by cosmographic parameters, arising from global constraints that inhibit a stable de Sitter universe.

arXiv commentUpdated conform invited talk at Corfu Summer Institute 2025 'Workshops on Tensions in Cosmology', PoS(Corfu2025)509:233, doi 10.22323/1.509.0233