Regime II as a Frontier: Delimiting the Classical, Quantum, and Geometric Gaps of the RCD Coherence Field

This is a positioning document, not a research paper. It delimits open problems; it does not derive, simulate, or validate any of them, and it contains no kill switch because it executes nothing. Its product is the delimitation itself: a map of which gaps separate the validated late-time RCD coherence-field kernel from the origins it would require to support a strong geometric claim. Taking as fixed input the validated Regime III coarsening model and the companion principal-symbol analysis showing that kernel to be strictly parabolic, this note separates three distinct gaps that informal discussion tends to collapse into one: (1) a classical gap — an inertial (telegraph) extension whose overdamped limit must reproduce Regime III, including the measured coarsening prefactor A = 7. 67 ± 0. 20, as a consistency condition; (2) a quantum gap — the absence of any microscopic action, classical or quantum, of which C is the derived order parameter, here stated as an aspiration of the program rather than a result; and (3) a geometric horizon — an emergent metric sector g_μν, named and deferred. The document argues that "loss of inertia" and "loss of the causal cone" are the same structural event, that the multiplicative Wright–Fisher noise of the validated equation is classical demographic noise (not a signature of a quantum bath), and that any cone restored by an inertial extension would be an acoustic analogue on a fixed FRW background, not emergent spacetime. The document asserts nothing about whether these gaps can be closed.