The Invariant Substrate: A Non-Zero Baseline Model for the Vacuum as a Charged Medium

This work proposes a baseline reinterpretation of the physical vacuum as an invariant, non-zero substrate rather than a true null state. The central claim is that the observed dynamical quietness of the vacuum does not require ontological emptiness, but may instead reflect calibration to a uniform background that produces no local signal under symmetric conditions.A gradient-based measurement principle is developed in which observables arise from departures from uniformity rather than from absolute baseline values. Within this framework, fields, forces, and energy-carrying structures are interpreted as deviations from a non-zero substrate rather than as excitations above literal nothingness.The model is presented as a conceptual and structural reinterpretation consistent with existing physical theories at the level of observables. It reframes the vacuum-energy problem by distinguishing between an unobservable baseline and observable residual structure, without claiming a complete dynamical replacement for quantum field theory or general relativity.This version (Version 1.0 — March 2026) represents a fully corrected and internally consistent master including reference verification, mathematical consistency checks, and hostile-referee hardening.