Can recent DESI BAO measurements accommodate a negative cosmological constant?

TL;DR

This study investigates whether recent DESI BAO measurements, combined with other cosmological data, support the existence of a negative cosmological constant, finding a slight preference but no definitive evidence.

Contribution

The paper performs a combined analysis of DESI BAO, Planck CMB, and Pantheon Plus supernova data to explore the possibility of a negative cosmological constant, highlighting the potential of upcoming surveys.

Findings

Negative CC is preferred at >68% significance level.

Negative CC can allow dark energy equation of state w ≥ -1.

No definitive evidence for negative CC was found.

Abstract

Anti-de Sitter vacuum, which correspond to a negative cosmological constant (CC), is theoretically important and well-motivated. However, whether it exists in reality or not has always been a controversial issue. In this paper, we perform the search for the negative CC using recent Dark Energy Spectroscopic Instrument (DESI) baryon acoustic oscillation measurements combined with Planck cosmic microwave background and Pantheon Plus supernova data. Though we did not find the evidence for negative CC, we observed the indication for it, the negative CC is preferred at $>68\%$ significance level, while such a negative CC can make the state equation of evolving dark energy component (coexisting with negative CC) $w\geqslant -1$. Our work highlights the potential of upcoming cosmological surveys to search for the negative CC.