Retention Beyond Dynamics: Observational Sensitivity to Persistence in Late-Time Cosmological Regimes

This paper proposes a minimal interpretive framework for studying persistence and coherence in late-time cosmological regimes where dynamical activity becomes weak, sparse, or statistically marginal. Rather than introducing new forces or revising established cosmological models, the work focuses on observational sensitivity to long-lived structure under post-dynamical conditions. A retentive term is introduced as an effective descriptive parameter for equilibrium-like coherence, alongside empirically accessible observational proxies such as correlation-time plateaus, low-frequency residual energy (“stilled heat”), and topological persistence. Particular emphasis is placed on methodological restraint and non-violation as necessary conditions for observing persistence-dominated systems without disturbing the phenomena under study. The framework is presented as complementary, limited in scope, and open to empirical scrutiny, offering a disciplined way to interpret late-time cosmological data where change itself becomes rare.