Redshift-binned constraints on the Hubble constant under , CPL, and Padé cosmography
Phys. Rev. D 113, 043516 – Published 13 February, 2026
DOI: https://doi.org/10.1103/cm3y-2nqq
Abstract
Motivated by recent claims of a possible redshift dependence in late-Universe determinations of the Hubble constant (), we test the robustness of this behavior using multiple cosmological probes. We perform a joint redshift-binned analysis of across eight bins using late-Universe probes—Pantheon+ type Ia supernova, Dark Energy Spectroscopic Instrument baryon acoustic oscillation, cosmic chronometers, and water megamasers—under three cosmological frameworks: flat cold dark matter, Chevallier-Polarski-Linder, and Padé cosmography. Under a common baseline scheme, all three models show a qualitatively similar, low-amplitude variation in the per-bin estimates. A simple Fourier-like parametrization captures this behavior, but the amplitude differs from zero only at a marginal significance of about , with similar behavior observed across all three cosmological frameworks. We then investigate the robustness and possible origin of this feature. Alternative binning schemes preserve its qualitative form, whereas single-probe per-bin fits (supernova-only, cosmic chronometer-only, BAO-only) yield ratios mostly consistent with unity and do not reproduce the pronounced drift seen in the joint baseline constraints. Finally, by comparing different global versus piecewise-constant configurations for , we find that a baselinelike oscillatory pattern reemerges only when multiple degenerate parameter combinations are allowed to vary across bins, while it is strongly suppressed when only is bin dependent. Taken together, these results indicate that the apparent oscillatory behaviour of in late-time arises from known parameter degeneracies and does not constitute robust evidence for a genuine redshift evolution.