Connecting primordial gravitational waves and dark energy

Cosmic acceleration manifested in the early universe as inflation, generating primordial gravitational waves detectable in the cosmic microwave background (CMB) radiation. Cosmic acceleration is occurring again at present as dark energy, detectable in cosmic distance and structure surveys. We explore the intriguing idea of connecting the two occurrences through quintessential inflation by an alpha-attractor potential without a cosmological constant. For this model we demonstrate robustness of the connection 1 + w0 approximate to 4/(3N2r) between the present day dark energy equation of state parameter w0 and the primordial tensor to scalar ratio r for a wide range of initial conditions. Analytic and numerical solutions produce current thawing behavior, resulting in a tight relation wa approximate to -1.53(1 + w0) approximate to -0.2 (4 x 10-3/r). Upcoming CMB and galaxy redshift surveys can test this consistency condition. Within this model, lack of detection of a dark energy deviation from Lambda predicts a higher r, and lack of detection of r predicts greater dark energy dynamics.

Automated summary

This study explores the connection between early universe inflation and present-day dark energy through quintessential inflation without a cosmological constant. The researchers demonstrate a robust relationship between the dark energy equation of state parameter and the primordial tensor to scalar ratio for a wide range of initial conditions. The study suggests that upcoming cosmic microwave background and galaxy redshift surveys can test the consistency condition.