The Hubble tension: Change in dark energy or a case for modified gravity?

TL;DR

This paper explores whether modifications to gravity on large scales could resolve the discrepancy in Hubble constant measurements from early universe CMB observations and local distance indicators.

Contribution

It proposes a modified gravity model as an alternative explanation for the Hubble tension, challenging the need for new dark energy components.

Findings

Suggests large-scale gravity modifications can reconcile Hubble constant differences.

Provides theoretical framework for alternative gravity models in cosmology.

Highlights potential implications for understanding cosmic acceleration.

Abstract

Recently much controversy has been raised about the cosmological conundrum involving the discrepancy in the value of the Hubble constant as implied by Planck satellite observations of the CMBR in the early Universe and that deduced from other distance indicators (for instance using standard candles like supernovae, tip of the Red Giant branch, etc.) in the present epoch. The Planck estimate is about 67 km/s/Mpc, while that deduced from distance indicators at the present epoch is around 73-74 km/s/Mpc. Also the independent determination of the local value of the Hubble constant based on a calibration of the Tip of the Red Giant Branch (TRGB) and applied to Type Ia supernovae found a value of 69.8 km/s/Mpc. Here we propose a modification of the gravitational field on large scales as an alternate explanation for this discrepancy in the value of the Hubble constant as implied in the above-mentioned method, i.e., by Planck observations of the CMBR in the early Universe and that deduced from other distance indicators in the present epoch.