Bimodal Regime Structure in Galactic Rotation Curves: Evidence for Distinct Dynamical States and a Field-Based Interpretation of the Dark Matter Effect

This work analyses 164 galactic rotation curves from the SPARC database and develops a field-based interpretation of the dark matter effect within the framework of the Universal Quantum Foam Hypothesis (UQSH). The empirical excess term C(r) = v2obs(r) - v2bar(r) reveals, after normalisation, a consistent structure of preferred dynamical regimes. 1 Global fits identify two dominant states: a peak regime with scale parameter q ≈ 0.5–1.0, encompassing mainly low-surface-brightness galaxies and dwarf galaxies, and a diffuse regime with q ≈ 3.0, dominated by more massive spiral galaxies. Individual fits yield a distribution of roughly 62% peak systems, 26% diffuse systems, and 12% in the transition zone. An analysis of the dynamic factor D = gobs/gbar as a function of the maximum rotation curve radius reveals a statistically significant negative correlation (r = -0.31, p = 0.0001). Beyond approximately 50–80 kpc, D converges systematically toward 1. This empirical instability boundary marks the spatial range within which coherent field organisation produces measurable amplification. In the UQSH, light is interpreted as a spherically propagating tension front that follows the accumulated field geometry. In this picture, the convergence κ does not measure the instantaneous mass density, but the projected field curvature. A UQSH model of the Bullet Cluster reproduces the characteristic order of magnitude of the offsets between gas centres and κ-peaks of 219 kpc and 228 kpc without requiring an additional non-baryonic matter component. In the UQSH, the dark matter effect is not a sign of missing particles but an intrinsic property of the field medium. Baryonic structures are stable field configurations that spatially pre-stress the field medium. Through continuous radiation they excite the field and generate persistent deformations that do not fully relax. The nonlinear superposition of these three sources — bound baryonic mass, continuous radiation, and the accumulated field pre-stress — produces a large-scale field tension that appears observationally as the dark matter effect. On galactic scales, the empirical instability boundary at approximately 50–80 kpc sets a natural spatial limit on this field tension. In galaxy clusters, the individual contributions of many saturated structures superpose into a collective field tension that systematically raises the lensing signal above the baryonic expectation. The universal fits show high internal consistency within each regime, with mean squared errors of MSE ≈ 0.016 in the peak regime and MSE ≈ 0.06–0.13 in the diffuse regime. This universality stands in contrast to the expectation from continuous halo models and supports the field-based interpretation of preferred dynamical states.