Cosmic clues: DESI, dark energy, and the cosmological constant problem

• Published in: The journal of high energy physics 2024-05, Vol.2024 (5), p.327-9, Article 327
• Main Author: Yin, Wen
• Format: Article
• Language: English
• Subjects: Astronomical models; Classical and Quantum Gravitation; Cosmological constant; Cosmology; Cosmology of Theories BSM; Dark energy; Elementary Particles; New Light Particles; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Quantum Physics; Regular Article - Theoretical Physics; Relativity Theory; Scalars; String Theory; Time dependence
• ISSN: 1029-8479; 1029-8479
• DOI: 10.1007/JHEP05(2024)327

A bstract 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 ΛCDM model and varies over time. In this paper, I show that the simple linear potential of a scalar field that may explain the small cosmological constant, can explain the DESI anomaly. The conclusions do not change by including or not including a thermal friction effect. In particular, the model proposed by the present author in [1], which relaxes the cosmological constant by the condition that inflation ends, predicts a time-dependence of the dark energy close to the one favored by the data.