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,nt) plane. We analyse 5 × 104 realizations of inflationary scenarios that respect the Null-Energy Condition (> 0) and 5 × 104 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: r0.002 < 0.056 at 95 % CL . We find that general EFT inflationary models with > 0 are typically characterized by nt < 0, whereas the vast majority of NEC-violating models presents a blue-tilted spectrum (nt > 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.

Let Effective Field Theory of inflation flow : stochastic generation of models with red/blue tensor tilt / G. Capurri, N. Bartolo, D. Maino, S. Matarrese. - In: JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS. - ISSN 1475-7516. - 2020:11(2020), pp. 037.1-037.23. [10.1088/1475-7516/2020/11/037]

Let Effective Field Theory of inflation flow : stochastic generation of models with red/blue tensor tilt

D. Maino;
2020

Abstract

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,nt) plane. We analyse 5 × 104 realizations of inflationary scenarios that respect the Null-Energy Condition (> 0) and 5 × 104 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: r0.002 < 0.056 at 95 % CL . We find that general EFT inflationary models with > 0 are typically characterized by nt < 0, whereas the vast majority of NEC-violating models presents a blue-tilted spectrum (nt > 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.
inflation; physics of the early universe; primordial gravitational waves (theory)
Settore FIS/05 - Astronomia e Astrofisica
Article (author)
File in questo prodotto:
File Dimensione Formato  
Capurri_2020_J._Cosmol._Astropart._Phys._2020_037.pdf

accesso aperto

Tipologia: Publisher's version/PDF
Dimensione 1.53 MB
Formato Adobe PDF
1.53 MB Adobe PDF Visualizza/Apri
Pubblicazioni consigliate

Caricamento pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/869205
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 5
  • ???jsp.display-item.citation.isi??? 5
social impact