Flow-Time Theory: Frequency Modulation, Multi-Layer Space Hypothesis, and the Cross-layer Frequency Resonance Experiment (CFRE)

This paper extends Flow-Time Theory (FTT) from entropy dynamics (v1-v3) to frequency-domain engineering. Building on the existence of the Φ field and the gradient-driven entropy law, we propose the Multi-Layer Space hypothesis: different frequency ranges of the Φ field correspond to distinct, co-existing layers of reality. The linear response relation ⟨J^μ⟩ = ξσ ∂^μ Φ is symmetric, implying bidirectional cross-layer coupling. We propose the Cross-layer Frequency Resonance Experiment (CFRE) as a falsifiable test: simultaneous transmission of a triple-band signature (DC-10 Hz, 2.4-10 GHz, 0.1-10 THz) into a shielded cavity, monitoring for nonlinear responses. Speculative applications (UAP, extreme frequency layers, philosophical interpretations) are confined to appendices. The P5 information retrieval protocol (v3) provides independent empirical support (Cohen's d > 0.8, p < 0.001) but is not required for v4 core predictions.