2020/06/30 by Giulia Capurri, Nicola Bartolo, Davide Maino +1 · 1 citation
Physics and Astronomy · #Black Holes and Theoretical Physics #Cosmological perturbation theory #Cosmology and Gravitation Theories #Effective field theory #Field (mathematics) #Inflation (cosmology) #Observable #Planck #Pulsars and Gravitational Waves Research #Spectral density #Spectral index #Tensor (intrinsic definition) #astro-ph.CO
paper · pdf · doi:10.1088/1475-7516/2020/11/037
published as JCAP11(2020)037 · 24 pages, 5 figures. Replaced to match the version to appear in JCAP
openalex created_date 2020/06/25 · arxiv created 2020/10/13 · openalex publication_date 2020/11/19 · arxiv updated 2020/11/23 · openalex updated_date 2026/08/05
We extend the method of Flow Equations to the Effective Field Theory framework of inflation, in order to investigate the observable predictions of a very broad class of inflationary models. Focusing our attention on the gravitational-wave sector, we derive a general expression for the consistency relation for effective models and provide a numerical implementation which allows to study how the generated models populate the ( r , n t ) plane. We analyse 5 × 10 4 realizations of inflationary scenarios that respect the Null-Energy Condition ( > 0) and 5 × 10 4 realizations that violate it ( < 0). In both cases, 90 % of the viable models are below the most recent upper bound on the tensor-to-scalar ratio from Planck and BICEP2/Keck Array BK15 data: r 0.002 < 0.056 at 95 % CL . We find that general EFT inflationary models with > 0 are typically characterized by n t < 0, whereas the vast majority of NEC-violating models presents a blue-tilted spectrum ( n t > 0). Since a blue tensor spectral index implies more power on small scales, this result is of considerable interest in view of a possible direct detection of the primordial gravitational-wave background.