Do cosmological observations allow a negative ??

In view of the recent measurement of H-0 from the Hubble Space Telescope and Supernova H0 for the Equation of State (SH0ES) team, we explore the possibility of existence of a negative cosmological constant [anti-de Sitter (AdS) vacua in the dark energy sector] in the Universe. In this regard, we consider quintessence fields on top of a negative cosmological constant and compare such construction with ? cold dark matter (?CDM) model using a different combination of cosmic microwave background, Type Ia supernova, baryon acoustic oscillation, and H-0 data. Various model comparison estimators show that quintessence models with a negative ? are either preferred over ?CDM or perform equally as the ?CDM model. This suggests that the presence of a negative ? (AdS ground state) in our Universe, which can naturally arise in string theory, is consistent with cosmological observations.

Automated summary

This study explores the possibility of a negative cosmological constant in the Universe and finds that it is consistent with observational data.