No-go guide for the Hubble tension : Late-time solutions

TL;DR

This paper presents a comprehensive analysis showing that both early-time and late-time modifications to resolve the Hubble tension are largely ruled out, suggesting the need for new physics or unidentified systematics.

Contribution

It introduces a global parametrization based on cosmic age (PAge) to evaluate late-time solutions without relying on sound-horizon priors, strengthening the no-go argument.

Findings

Both early-time and late-time solutions are largely ruled out.

The PAge parametrization effectively tests late-time scenarios.

Standard modifications cannot fully resolve the Hubble tension.

Abstract

The Hubble tension, if not caused by any systematics, could be relieved or even resolved from modifying either the early-time or late-time Universe. The early-time modifications are usually in tension with either galaxy clustering or galaxy lensing constraints. The late-time modifications are also in conflict with the constraint from the inverse distance ladder, which, however, is weakened by the dependence on a sound-horizon prior and some particular approximation for the late-time expansion history. To achieve a more general no-go argument for the late-time scenarios, we propose to use a global parametrizationbased on the cosmic age (PAge) to consistently use the cosmic chronometers data beyond the Taylor expansion domain and without the input of a sound-horizon prior. Both the early-time and late-time scenarios are therefore largely ruled out, indicating the possible ways out of the Hubble tension from either exotic modifications of our concordance Universe or some unaccounted systematics.