Redshift Duality with Pantheon+SH0ES in a Planck-anchored Flat ΛCDM Framework: Implications for Hubble Tension and Observational Inference

Abstract We test an operationally defined redshift duality in which the observed redshift comprises the standard metric-expansion component together with an additional line-of-sight quantum contribution arising from the cumulative conversion of photon energy into effective mass as a function of path length and frequency. Fitting this hybrid model to the Pantheon+SH0ES compilation, we find that the metric-expansion Hubble constant, $H_\Lambda$, is recovered to a value consistent with the Planck baseline of 67.4 km s−1 Mpc−1 within ≲ 0.33σ. Redshift-binned analyses show that while the flat ΛCDM model produces an apparent drift in the inferred Hubble parameter across the Hubble flow, the hybrid model restores the constancy of $H_\Lambda$ across redshift bins. The correctional trends of cosmological physical quantities re-inferred under this framework further indicate the potential to alleviate anomalies associated with high-redshift galaxies. These results suggest that redshift duality warrants further consideration in observational processing and inference, while preserving consistency with a Planck-anchored flat ΛCDM baseline.