Phase-Model Paper 11: A Phase-Amplitude Fixed-Point Closure Model for Solitons

Version note (v2.0, 2026-04-06): This release updates editorial consistency across the Phase-Model series (Papers 01–13), including reference formatting, author-name normalization, and removal of local-path citation strings. The core model claims and rejection logic are unchanged unless explicitly stated below. This preprint proposes a phase-amplitude fixed-point closure model for solitons. The framework models soliton persistence via coupled dispersion, nonlinearity, and phase-rigidity terms, introduces measurable shape and phase stability indices, and defines explicit rejection criteria under controlled noise and collision experiments.