Hubble Tension: The Evidence of New Physics

TL;DR

This paper reviews the Hubble tension, highlighting discrepancies in Hubble constant measurements and exploring potential new physics beyond the standard cosmological model, especially modifications to late-time universe dynamics.

Contribution

It synthesizes recent research on the Hubble tension and evaluates evidence suggesting new physics, focusing on modifications to late-time cosmology.

Findings

Hubble constant measurements show a 4-6 sigma discrepancy.

Evidence favors new physics affecting late-time universe.

Modifications to the $ ext{Λ}$CDM model may resolve the tension.

Abstract

The $\Lambda$CDM model provides a good fit to most astronomical observations but harbors large areas of phenomenology and ignorance. With the improvements in the precision and number of observations, discrepancies between key cosmological parameters of this model have emerged. Among them, the most notable tension is the 4$\sigma$ to 6$\sigma$ deviation between the Hubble constant ($H_{0}$) estimations measured by the local distance ladder and the cosmic microwave background (CMB) measurement. In this review, we revisit the $H_{0}$ tension based on the latest research and sort out evidence from solutions to this tension that might imply new physics beyond the $\Lambda$CDM model. The evidence leans more towards modifying the late-time universe.