English

General dynamical properties of cosmological models with nonminimal kinetic coupling

General Relativity and Quantum Cosmology 2018-01-24 v2 Cosmology and Nongalactic Astrophysics High Energy Physics - Theory

Abstract

We consider cosmological dynamics in the theory of gravity with the scalar field possessing the nonminimal kinetic coupling to curvature given as ηGμνϕ,μϕ,ν\eta G^{\mu\nu}\phi_{,\mu}\phi_{,\nu}, where η\eta is an arbitrary coupling parameter, and the scalar potential V(ϕ)V(\phi) which assumed to be as general as possible. With an appropriate dimensionless parametrization we represent the field equations as an autonomous dynamical system which contains ultimately only one arbitrary function χ(x)=8πηV(x/8π)\chi (x)= 8 \pi \vert \eta \vert V(x/\sqrt{8 \pi}) with x=8πϕx=\sqrt{8 \pi}\phi. Then, assuming the rather general properties of χ(x)\chi(x), we analyze stationary points and their stability, as well as all possible asymptotical regimes of the dynamical system. It has been shown that for a broad class of χ(x)\chi(x) there exist attractors representing three accelerated regimes of the Universe evolution, including de Sitter expansion (or late-time inflation), the Little Rip scenario, and the Big Rip scenario. As the specific examples, we consider a power-law potential V(ϕ)=M4(ϕ/ϕ0)σV(\phi)=M^4(\phi/\phi_0)^\sigma, Higgs-like potential V(ϕ)=λ4(ϕ2ϕ02)2V(\phi)=\frac{\lambda}{4}(\phi^2-\phi_0^2)^2, and exponential potential V(ϕ)=M4eϕ/ϕ0V(\phi)=M^4 e^{-\phi/\phi_0}.

Keywords

Cite

@article{arxiv.1703.04966,
  title  = {General dynamical properties of cosmological models with nonminimal kinetic coupling},
  author = {Jiro Matsumoto and Sergey V. Sushkov},
  journal= {arXiv preprint arXiv:1703.04966},
  year   = {2018}
}

Comments

31 pages, 5 figures, 3 tables. New section "Slow-roll regime" added, references added, sentences polished. Version accepted for publication in JCAP