Cosmic Clues: DESI, Dark Energy, and the Cosmological Constant Problem

Understand

Several attempts to solve the cosmological constant problem, which concerns the value of the cosmological constant being extremely smaller than the Standard Model mass scales, have introduced a scalar field with a very flat potential that can be approximated as linear around any given position.

• The scalar field scans the cosmological constant in such a way that the current small value is explained.
• Recently, Dark Energy Spectroscopic Instrument (DESI) reported the results of the first year.
• Combining the data with CMB, Pantheon, Union3, and/or DES-SN5YR, there is a preference or anomaly, indicating that the dark energy in the current Universe slightly deviates from that in the $\Lambda$CDM model and varies over time.