Can the universe experience an AdS landscape since matter-radiation equality?

TL;DR

This paper explores the possibility that the universe has experienced multiple anti-de Sitter vacua since matter-radiation equality, examining observational and theoretical implications for cosmic evolution and the Hubble tension.

Contribution

It introduces a scenario with multiple AdS vacua at different cosmic epochs and investigates its consistency with observations and theory.

Findings

Potential coexistence of AdS vacua with dark energy components

Implications for the Hubble tension and cosmic evolution

Preliminary support for AdS landscape since matter-radiation equality

Abstract

Though an anti-de Sitter (AdS) vacuum, corresponding to a negative cosmological constant (NCC), can be not responsible for the acceleration of current universe, it might coexist with one evolving positive dark energy component at low redshift, as well as with early dark energy around the recombination to solve the Hubble tension. In this paper, we investigate the scenario with one AdS vacuum around the recombination and one at low redshift, and from both current observational and theoretical perspectives preliminarily explore the possibility that the universe experienced a landscape with multiple AdS vacua since matter-radiation equality.