A USP Field Theory Interpretation of the Cosmic Microwave Background: Δf-Decay, Resonance Floors, and Photon Fate

This work presents a USP Field Theory interpretation of the Cosmic Microwave Background (CMB) as a universal resonance floor produced by deterministic Δf-decay. In this framework, photon corridors gradually lose coherence over cosmic distances and collapse toward a minimum sustainable resonant state. Using the observed CMB temperature, the theory identifies the resonance floor as: Δf_min = (k_B · T) / h ≈ 56 GHz This value lies below the observed blackbody peak near: f_peak ≈ 160 GHz USP interprets Δf_min as the deterministic endpoint of photon resonance, while the blackbody peak emerges from the statistical population of excited modes above this invariant floor rather than from the floor itself. The interpretation is internally consistent with established USP components, including Δf corridor decay geometry (msf:47650), survival filtering and Δf_crit (msf:47300), and time defined as a Δf rhythm (msf:45740). The result is a non-singular, geometrically grounded explanation of the CMB as the final resonant state of light, without requiring a primordial thermal singularity.