The Fluid Cosmic Crystal Theory (TCCF): Version 0.3 Phenomenological Phase Dynamics, Metric Interpolation, and Experimental Observables

This submission presents Version 0.3 of the Fluid Cosmic Crystal Theory (FCCT/TCCF). Building upon the structural and thermodynamic foundations established in v0.2, this iteration advances the framework into a consolidated, testable phenomenological model. Within this updated formulation, spacetime is modeled as a structured thermodynamic substrate characterized by a scalar order parameter field. Phenomena traditionally described as geometric singularities are rigorously reinterpreted as critical topological phase transitions of the vacuum. To address divergent curvature in General Relativity, v0.3 introduces an effective metric interpolation that regularizes singular behavior, alongside a mathematically defined stability condition for localized matter (solitons). The most significant advancement in Version 0.3 is the transition from conceptual formalism to direct experimental falsifiability. By deriving the linear excitation sector of the substrate, this paper proposes a concrete interferometric signature: a predictable high-frequency deviation in the cross-power spectral density between spatially separated detectors. This provides a clear, observational pathway for next-generation UHF interferometers to constrain the structural coherence scale of spacetime.