Inflationary gravitational wave background as a tail effect
General Relativity and Quantum Cosmology
2023-11-29 v2 Cosmology and Nongalactic Astrophysics
High Energy Physics - Phenomenology
Abstract
The free propagator of a massless mode in an expanding universe can be written as a sum of two terms, a lightcone and a tail part. The latter describes a subluminal (time-like) signal. We show that the inflationary gravitational wave background, influencing cosmic microwave background polarization, and routinely used for constraining inflationary models through the so-called ratio, originates exclusively from the tail part.
Keywords
Cite
@article{arxiv.2303.17985,
title = {Inflationary gravitational wave background as a tail effect},
author = {Niko Jokela and K. Kajantie and M. Laine and Sami Nurmi and Miika Sarkkinen},
journal= {arXiv preprint arXiv:2303.17985},
year = {2023}
}
Comments
8 pages. v2: minor updates