2024/07/25 by Vivian Poulin, Poulin, Vivian, Tristan L. Smith +5 · 2 citations
Earth and Planetary Sciences · Physics and Astronomy · #Cosmology and Gravitation Theories #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #Dark Matter and Cosmic Phenomena #Earth Systems and Cosmic Evolution #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph)
paper · pdf · doi:10.48550/arxiv.2407.18292
openalex publication_date 2024/07/25 · openalex created_date 2024/08/01 · openalex updated_date 2026/08/04
The `cosmic calibration tension' is a > 5σ discrepancy between the cosmological distance ladder built from baryonic acoustic oscillations (BAO) calibrated by the Planck/ΛCDM sound horizon (rs) and Type Ia supernovae (SN1a) calibrated instead with the SH0ES absolute magnitude, assuming the distance-duality relationship (DDR) holds. In this work, we emphasize the consequences of this tension beyond the value of the Hubble constant H0, and the implications for physics beyond ΛCDM. Of utmost importance, it implies a larger physical matter density ωm≡ Ωm h2, as both the fractional matter density Ωm and h≡ H0/100 km/s/Mpc are well constrained from late-time data. New physics in the pre-recombination era must thus be able to decrease rs while either reducing the value of Ωm, or increasing the value of ωm. Assuming a ΛCDM-like primordial power spectrum, this necessarily results in an increase in the clustering amplitude σ8. Deviations from ΛCDM in the late-time expansion history cannot resolve the calibrator tension but can help relax the required shifts to the matter density and σ8: it is in that sense that a combination of early and late-time new physics may help alleviate the tension. More precisely, models that modify the pre-recombination expansion history can accommodate the increase in ωm without the need for additional modifications. It is those models which only affect recombination that require additional deviations at late-times to be successful. Hence, the `cosmic calibration tension' points either to a targeted modification of the pre-recombination expansion history, or to a broader change affecting multiple cosmic epochs.