Scalar-induced gravitational waves in a ΛCDM cosmology

• Verfasst von: Sipp, Marvin [VerfasserIn]
• Verfasst von: Schäfer, Björn Malte [VerfasserIn]
• Titel: Scalar-induced gravitational waves in a ΛCDM cosmology
• Verf.angabe: Marvin Sipp, Björn Malte Schäfer
• E-Jahr: 2023
• Jahr: 24 March 2023
• Umfang: 12 S.
• Fussnoten: Gesehen am 24.05.2023
• Titel Quelle: Enthalten in: Physical review
• Ort Quelle: Ridge, NY : American Physical Society, 2016
• Jahr Quelle: 2023
• Band/Heft Quelle: 107(2023), 6 vom: März, Artikel-ID 063538, Seite 1-12
• ISSN Quelle: 2470-0029
• DOI: doi:10.1103/PhysRevD.107.063538
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1846102782

Abstract

We reconsider the gravitational wave spectrum induced by scalar perturbations in spatially flat Friedmann-Lemaître-Robertson-Walker spacetimes, focusing on the matter- and Λ-dominated epochs. During matter domination, subhorizon modes are not free, and a commonly applied approximation for the derivative of the tensor perturbation is flawed. We show analytically that this leads to a significant overestimation of the energy density spectrum. In addition, we demonstrate that gauge-dependent nonoscillating tensor perturbations appear in the presence of a cosmological constant. Complementing the analytical calculations, we compute the according present-day spectrum numerically for a Planck-like ΛCDM cosmology, finding that nonoscillating growing modes appear during the transition between matter and Λ domination in conformal Newtonian gauge.