Horizon-Driven Expansion from Hawking-Like Radiation: A Curvature-Coupled Cosmological Model

Abstract: We propose a cosmological model in which the expansion of the universe is driven by a Hawking-like influx of energy across the cosmological horizon, rather than from a fixed cosmological constant. In place of a cosmological constant, we introduce source terms in the Friedmann and continuity equations that couple horizon curvature to matter and radiation densities. At high curvature (large Hubble parameter $H$), this influx strongly replenishes matter and radiation, slowing their adiabatic dilution. As curvature diminishes, the influx weakens, smoothly transitioning into standard radiation- or matter-dominated eras. This mechanism naturally suppresses spatial curvature without requiring an inflationary phase. It may also produce near-scale-invariant fluctuations via slowly varying horizon thermodynamics.