USP Field Theory — Why Δf Rejection Cannot Be Accepted

This document consolidates a cornerstone principle of USP Field Theory: the Δf (frequency mismatch) mechanism. It argues that Δf is the fundamental oscillatory process unifying light, heat, phonons, and electrical current. The work explains why Δf cannot be rejected conceptually, shows how apparent laboratory “rejections” are instead limits of measurement precision, and reframes even basic temperature measurement as an entanglement of oscillations via Δf transfer. By combining logical progression, real-world examples, and experimental implications, this milestone record establishes Δf as a non-negotiable foundation of USP Field Theory. 🔹 Harmonization Note (DOI Integration) This publication is harmonized with the experimental foundation established in USP Field Theory – Temperature & Resonance: Testable Experiments (2025), DOI: 10.5281/zenodo.16788099. That work defines the laboratory verification path for Δf relaxation, η-controlled transparency, and resonant thermal emission, providing the testable framework for all Δf-based temperature, energy, and transparency laws across the USP Field Theory series (msf: 45706 – 45714).