Can recent DESI BAO measurements accommodate a negative cosmological constant?

Understand

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) $w\geqslant -1$.