Coupled scalar fields in the late Universe: The mechanical approach and the late cosmic acceleration

Abstract

In this paper, we consider the Universe at the late stage of its evolution and deep inside the cell of uniformity. At these scales, we consider the Universe to be filled with dust-like matter in the form of discretely distributed galaxies, a minimally coupled scalar field and radiation as matter sources. We investigate such a Universe in the mechanical approach. This means that the peculiar velocities of the inhomogeneities (in the form of galaxies) as well as fluctuations of other perfect fluids are non-relativistic. Such fluids are designated as coupled because they are concentrated around inhomogeneities. In the present paper we investigate the conditions under which a scalar field can become coupled, and show that, at the background level, such coupled scalar field behaves as a two component perfect fluid: a network of frustrated cosmic strings with EoS parameter $w=-1/3$ and a cosmological constant. The potential of this scalar field is very flat at the present time. Hence, the coupled scalar field can provide the late cosmic acceleration. The fluctuations of the energy density and pressure of this field are concentrated around the galaxies screening their gravitational potentials. Therefore, such scalar fields can be regarded as coupled to the inhomogeneities.

arXiv comment14pages, 1 figure

References in corpus (28)

• Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant
• Measurements of Omega and Lambda from 42 High-Redshift Supernovae
• Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Parameter Results
• A Phantom Menace? Cosmological consequences of a dark energy component with super-negative equation of state
• Quintessence, Cosmic Coincidence, and the Cosmological Constant
• Can the dark energy equation-of-state parameter w be less than -1?
• Cluster Abundance Constraints on Quintessence Models
• Quintom Cosmology: Theoretical implications and observations
• Structure formation with a self-tuning scalar field
• Correspondence between kinematical backreaction and scalar field cosmologies - the `morphon field'
• N-body methods for relativistic cosmology
• First-order Cosmological Perturbations Engendered by Point-like Masses
• Structure formation with scalar field dark matter: the field approach
• Structure Formation with Scalar Field Dark Matter: The Fluid Approach
• Dynamics of astrophysical objects against the cosmological background
• Discrete Newtonian Cosmology
• Remarks on mechanical approach to observable Universe
• Hubble flows and gravitational potentials in observable Universe
• Slow-Roll Inflation Preceded by a Topological Defect Phase à la Chaplygin Gas
• Rigorous theoretical constraint on constant negative EoS parameter $\omega$ and its effect for the late Universe
• Scalar perturbations in the late Universe: viability of the Chaplygin gas models
• Are dark energy models with variable EoS parameter $w$ compatible with the late inhomogeneous Universe?
• Discrete Newtonian Cosmology: Perturbations
• Scalar perturbations in cosmological models with quark nuggets
• Perfect fluids coupled to inhomogeneities in the late Universe
• Cosmic antigravity

Cited by in corpus (4)

• $K$-essence model from the mechanical approach point of view: coupled scalar field and the late cosmic acceleration
• Cosmological screening and the phantom braneworld model
• Gravitational Foundations and Exact Solutions in $n$-Dimensional Fractional Cosmology
• Scalar perturbations of Galileon cosmologies in the mechanical approach within the late Universe