The Hubble Tension as an Infrared Closure Failure: A Relaxative CLEO–LOP Interpretation

The persistent discrepancy between early- and late-time determinations of the Hubble constant is usually framed as a disagreement between inferred values of the same cosmological parameter. The central claim of the present work is stronger and more structural: the tension is argued to be the observational imprint of an infrared closure failure. Within the CLEO–LOP framework, the late-time expansion history is not treated as the trivial output of a purely local background law, but as a bounded causal–entropic flow governed by the infrared state variable u(N) ≡ −dlnH2 dN , N≡lna. (1) The key quantity tested in this work is the closure observable C(z) ≡ u′ u(3 −u) , (2) which isolates the dynamical structure beyond the universal bounded infrared factors. Using late-time background probes — cosmic chronometers, Pantheon+ supernovae, and DESI baryon acoustic oscillations — the reconstructed C(z) is confronted with local and non-local closure classes. The analysis shows that the local class is decisively rejected, while a minimal causal non-local extension with relaxative memory is overwhelmingly favored. In this preferred sector, the inferred value of the Hubble constant becomes closure-dependent and is shifted upward relative to the local minimal class, toward the late-time side of the observed tension. The significance of this result is physical rather than merely statistical. It implies that late-time cosmic acceleration is not most naturally described as the output of a rigid local prescription, but as the endpoint of a history-dependent infrared relaxation process. In this interpretation, the Hubble tension is elevated from a parameter discrepancy to a direct observational probe of the dynamical nature of cosmic acceleration itself.