2020/09/30 by Hao-Hao Li, Gen Ye, Yun-Song Piao
Chemistry · Earth and Planetary Sciences · Physics and Astronomy · #Astrophysics #Cascade #Chemistry #Computer science #Cosmology and Gravitation Theories #Geophysics and Gravity Measurements #Gravitational wave #Gravitational wave background #Inflation (cosmology) #Nuclear physics #Physics #Pulsars and Gravitational Waves Research #SIGNAL (programming language) #Theoretical physics #astro-ph.CO #gr-qc #hep-th
paper · pdf · doi:10.1016/j.physletb.2021.136211
12 pages,3 figures, published version
openalex publication_date 2021/03/18 · arxiv created 2021/03/21 · arxiv updated 2021/03/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The NANOGrav collaboration recently has reported evidence for a stochastic common-spectrum process in its 12.5 yr dataset. We show that such a signal might be a hint of de Sitter (dS) decay during inflation. As suggested by the swampland conjectures, dS space is highly unstable if it exists at all. During inflation, the short-lived dS states will decay through a cascade of first-order phase transitions (PT). We find that the gravitational waves (GWs) yielded by such a PT will be “reddened” by subsequent dS expansion, which may result in a slightly red-tilt stochastic GW background at the low-frequency band, compatible with the NANOGrav 12.5 yr result.