Scalar perturbations of Galileon cosmologies in the mechanical approach within the late Universe

Abstract

We investigate the Universe at the late stage of its evolution and inside the cell of uniformity 150-370 Mpc. We consider the Universe to be filled at these scales with dust like matter, a minimally coupled Galileon field and radiation. We use the mechanical approach. Therefore, the peculiar velocities of the inhomogeneities as well as the fluctuations of the other perfect fluids can be considered nonrelativistic. Such fluids are said to be coupled because they are concentrated around the inhomogeneities. We investigate the conditions under which the physical Galileon field, i.e. compatible with results of the latest gravitational wave experiments GW150914, GW151226, GW170104, GW170814, GW170817 and GW170608, can become coupled. We know that at the background level coupled scalar fields behave as a two-component perfect fluids: one which mimics a network of frustrated cosmic string and an another one which corresponds to an effective cosmological constant. We found a correction for the Galileon field, which behaves like a matter component.

arXiv comment8 pages

References in corpus (21)

• Extended Theories of Gravity
• The Case for a Positive Cosmological Lambda-term
• The galileon as a local modification of gravity
• Chameleon Cosmology
• Dark Energy after GW170817: dead ends and the road ahead
• Dark Energy
• An introduction to the Vainshtein mechanism
• Generalized Galileon cosmology
• First-order Cosmological Perturbations Engendered by Point-like Masses
• Dynamics of astrophysical objects against the cosmological background
• Cosmological perturbations in an effective and genuinely phantom dark energy Universe
• Remarks on mechanical approach to observable Universe
• Hubble flows and gravitational potentials in observable Universe
• Rigorous theoretical constraint on constant negative EoS parameter $\omega$ and its effect for the late Universe
• k-essence in the DGP brane-world cosmology
• $f(R)$ gravity: scalar perturbations in the late Universe
• Are dark energy models with variable EoS parameter $w$ compatible with the late inhomogeneous Universe?
• Scalar perturbations in cosmological models with quark nuggets
• $K$-essence model from the mechanical approach point of view: coupled scalar field and the late cosmic acceleration
• Perfect fluids coupled to inhomogeneities in the late Universe
• Coupled scalar fields in the late Universe: The mechanical approach and the late cosmic acceleration