Fluid Cosmic Crystal Theory (FCCT v0.2): Structural Dynamics of the Vacuum, Emergent Gravity, and Cosmological Evolution

This submission presents Version 0.2 of the Fluid Cosmic Crystal Theory (FCCT), advancing the framework from a static elastic lattice model to a fully dynamic thermodynamic substrate. This updated theoretical framework introduces a dimensionless structural control parameter (χ) to mathematically quantify the competition between macroscopic vacuum coherence and topological defect accumulation. By establishing a system of coupled structural evolution equations, FCCT v0.2 demonstrates how the thermodynamic collapse of vacuum rigidity naturally yields late-time cosmological acceleration (Dark Energy equivalence) through a state of meta-stable dynamic equilibrium. Furthermore, the model derives a modified Poisson equation for an inhomogeneous elastic medium that exactly recovers the asymptotic Baryonic Tully-Fisher Relation at the galactic scale. This provides a rigorous, testable elastodynamic mechanism for emergent gravity that fundamentally eliminates the necessity for particulate Dark Matter halos.