Space Field Medium Theory: A Falsifiable Fifth-Force Unification Framework

This paper proposes the Space Field Medium Theory—a testable framework positing that space is a physical quantum medium with ground-state rigidity, giving rise to a fifth fundamental force. From three axioms, two core constants (\gamma = 0.08, V_z = 25) are derived from the topological entanglement network and unified via the Kibble-Zurek mechanism. The theory yields a modified Friedmann equation, explains dark energy and Hubble tension, and provides an exponential cutoff transfer function for structure formation. It unifies vacuum fluctuations, virtual particle realization, and the Casimir effect as manifestations of the same medium, gives a complete chain from quarks to cosmic structure, and explains stellar evolution through black holes. Four tabletop experiments are predicted, each with precise falsification conditions keyed to \gamma.