The Breathing Universe: 308 Minimal Dynamical Core of the Breathing Universe

This paper develops a minimal dynamical formulation of vacuum-tension dynamics within the Breathing Universe framework using the language of covariant effective field theory. The central element of the formulation is a scalar order parameter H(x), interpreted as a coarse-grained measure of local vacuum-tension imbalance relative to a canonical equilibrium configuration known as the zero-line. Rather than introducing a new fundamental force sector, the scalar field functions as an effective descriptor of redistribution imbalance within a structured vacuum. Starting from a generally covariant action with a canonical kinetic term and quartic potential, the work derives the scalar field equation, the associated stress–energy tensor, and the coupled Einstein equations governing the scalar–tensor system. Linearization around a slowly varying background configuration yields controlled corrections to gravitational wave propagation while preserving the infrared limit in which General Relativity is recovered. The framework is constructed explicitly as an effective theory valid below a cutoff scale M*. Higher-derivative operators generate dispersive corrections to tensor-mode propagation that remain perturbatively suppressed in the infrared regime. The resulting modified dispersion relation connects observable gravitational wave signatures directly to the underlying parameters of the effective theory. The construction preserves general covariance, local energy–momentum conservation, and compatibility with the effective field theory interpretation of gravity. Its purpose is not to replace General Relativity but to provide a mathematically explicit dynamical core for the vacuum-balance structure previously introduced in the Breathing Universe framework. This formulation establishes the theoretical foundation required for quantitative phenomenological tests of vacuum-tension dynamics.