2020/03/31 by William Giarè, Alessandro Melchiorri, A. Melchiorri
Earth and Planetary Sciences · Physics and Astronomy · #Amplitude #Anisotropy #Astrophysics #Black Holes and Theoretical Physics #Classical mechanics #Cosmic microwave background #Cosmology #Cosmology and Gravitation Theories #Einstein #Einstein Telescope #Geophysics and Gravity Measurements #Gravitation #Gravitational wave #Gravitational wave background #Inflation (cosmology) #LIGO #Physics #Quantum mechanics #Spectral density #Theoretical physics #astro-ph.CO
paper · pdf · doi:10.1016/j.physletb.2021.136137
published as Phys. Lett. B 815 (2021) 136137 · 12 Pages, 4 figures. Edited to match Phys. Lett. B published version
openalex created_date 2020/03/23 · openalex publication_date 2021/02/11 · arxiv created 2021/02/16 · arxiv updated 2021/02/17 · openalex updated_date 2026/08/05
The detection of Primordial Gravitational Waves (PGWs) is one of the most important goals of modern cosmology since PGWs can both provide substantial evidence for primordial inflation and shed light on its physical nature. Small scale experiments on gravitational waves such as LIGO/VIRGO and, in future, LISA and Einstein Telescope (ET), being sensitive to the stochastic background of gravitational waves, can be used together with the CMB data to constrain the inflationary parameters. In performing these analyses the primordial tensor spectrum is usually parametrized with a power law that includes only the amplitude and a scale independent tilt. In this paper, we investigate the robustness of assuming the tensor tilt as scale independent. We show that due to the huge difference in the scales probed by CMB and GWs data, even a small scale dependence can remarkably affect the shape of the primordial spectrum possibly breaking the power-law assumption. When the non-linear corrections are considered the final constraints can be significantly changed. We also study the scale dependence in two different physical models of inflation providing an example of negligible scale dependence and an example of non-negligible scale dependence.