Gravitational Wave Spectrum Induced by Primordial Scalar Perturbations
Journal
Phys.Rev.D76:084019,2007
Journal Volume
76
Journal Issue
8
Date Issued
2007-03-31
Author(s)
Abstract
We derive the complete spectrum of gravitational waves induced by primordial
scalar perturbations ranging over all observable wavelengths. This
scalar-induced contribution can be computed directly from the observed scalar
perturbations and general relativity and is, in this sense, independent of the
cosmological model for generating the perturbations. The spectrum is
scale-invariant on small scales, but has an interesting scale-dependence on
large and intermediate scales, where scalar-induced gravitational waves do not
redshift and are hence enhanced relative to the background density of the
Universe. This contribution to the tensor spectrum is significantly different
in form from the direct model-dependent primordial tensor spectrum and,
although small in magnitude, it dominates the primordial signal for some
cosmological models. We confirm our analytical results by direct numerical
integration of the equations of motion.
Subjects
High Energy Physics - Theory; High Energy Physics - Theory; Astrophysics; General Relativity and Quantum Cosmology
Description
19 pages, 5 figures
Type
journal article