Scaling solutions and weak gravity in dark energy with energy and momentum couplings

• Verfasst von: Amendola, Luca [VerfasserIn]
• Verfasst von: Tsujikawa, Shinji [VerfasserIn]
• Titel: Scaling solutions and weak gravity in dark energy with energy and momentum couplings
• Verf.angabe: Luca Amendola and Shinji Tsujikawa
• E-Jahr: 2020
• Jahr: 9 June 2020
• Fussnoten: Gesehen am 01.09.2020
• Titel Quelle: Enthalten in: Journal of cosmology and astroparticle physics
• Ort Quelle: London : IOP, 2003
• Jahr Quelle: 2020
• Band/Heft Quelle: (2020,6) Artikel-Nummer 020, 21 Seiten
• ISSN Quelle: 1475-7516
• DOI: doi:10.1088/1475-7516/2020/06/020
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1728486149

Abstract

We argue that the ΛCDM tensions of the Hubble-Lemaȋtre expansion rate H0 and the clustering normalization σ8 can be eased, at least in principle, by considering an interaction between dark energy and dark matter in such a way to induce a small and positive early effective equation of state and a weaker gravity. For a dark energy scalar field ϕ interacting with dark matter through an exchange of both energy and momentum, we derive a general form of the Lagrangian allowing for the presence of scaling solutions. In a subclass of such interacting theories, we show the existence of a scaling ϕ-matter-dominated-era (ϕMDE) which can potentially alleviate the H0 tension by generating an effective high-redshift equation of state. We also study the evolution of perturbations for a model with ϕMDE followed by cosmic acceleration and find that the effective gravitational coupling relevant to the linear growth of large-scale structures can be smaller than the Newton gravitational constant G at low redshifts. The momentum exchange between dark energy and dark matter plays a crucial role for realizing weak gravity, while the energy transfer is also required for the existence of ϕMDE.