2-field model of dark energy with canonical and non-canonical kinetic terms
Journal Title: Odessa Astronomical Publications - Year 2018, Vol 31, Issue
Abstract
For some parametrizations of the dark energy equation of state that varies in time there is transition from quintessence to phantom or vice versa at a certain redshift. Quintom – the 2-field model with 2 canonical kinetic terms (one with the “+” sign for quintessence and one with the “-” sign for phantom) and a potential U(φ, ξ) in Lagrangian – is one of the most popular scalar field models allowing for such behaviour. We generalize quintom to include the tachyonic kinetic term along with the classical one. For such a model we obtain the expressions for energy density and pressure. For the spatially flat, homogeneous and isotropic Universe with Friedmann-Robertson-Walker metric of 4-space we derive the equations of motion for the fields. We discuss in detail the reconstruction of the scalar fields potential U(φ, ξ). Such a reconstruction cannot be done unambiguously, so we consider 3 simplest forms of U(φ, ξ): the product of Φ(φ) and Ξ(ξ), the sum of Φ(φ) and Ξ(ξ) and the sum of Φ(φ) and Ξ(ξ) to the κth power. The second additional assumption that should be made is about the dependence of either kinetic term Xφ or Xξ on the scale factor a. For each case we obtain the reconstructed potentials in the parametric form. If it is possible to invert dependences of the fields φ and ξ on the scale factor a and obtain the analytical expressions for a(φ) and a(ξ) then we can find the potentials U(φ, ξ) in explicit form. From the obtained explicit expressions it is clear that they are not suitable for practical use for the multicomponent cosmological models with realistic parametrizations of the dark energy equation of state crossing −1. On the other hand, the parametric dependences which define the potential U(φ, ξ) are suitable for multicomponent cosmological models and all parametrizations of the dark energy equation of state.
Authors and Affiliations
O. Sergijenko
Keywords
Related Articles
- EP ID EP603576
- DOI 10.18524/1810-4215.2018.31.144667
- Views 61
- Downloads 0
SPECTROSCOPIC INVESTIGATIONS OF GALACTIC CLUSTERS WITH ASSOCIATED CEPHEID VARIABLES. II. NGC 5662 AND V CEN
We present the results of a spectroscopic and photometric investigation of 15 objects from the open cluster NGC 5662, which contains the Cepheid V Cen. Besides the Cepheid, we studied one G-supergiant, two K-giants, four...
SCIENTIFIC ASTRONOMICAL SCHOOL BY PROFESSOR VOLODYMYR P. TSESEVICH ON THE PHYSICS OF VARIABLE STARS
I. B. Vavilova This paper is dedicated to the Prof. Volodymyr Platonovych Tsesevich (1907–1983), an outstanding scientist and legendary personality of the XX century. We describe briefly the Kyiv period of his life and...
LONGTERM CHANGES OF SOLAR ACTIVITY ASYMMETRY
We report results of analysis of the northsouth asymmetry of solar activity, solar magnetic fields. The analysis is based on the sunspot data, 1875–2015 (http://solarscience.msfc.nasa.gov/greenwch.shtml), largescale sola...
THE KINEMATICS PARAMETERS OF THE GALAXY USING DATA OF MODERN ASTROMETRIC CATALOGUES
Based on the Ogorodnikov-Milne model, we analyze the proper motions of XPM2, UCAC4 and PPMXL stars. To estimate distances to the stars we used the method of statistical parallaxes herewith the random errors of the distan...
RE-CLASSIFICATION OF THE NEGLECTED VARIABLE V480 AQL
We present the results of multicoloured photometric study of previously neglected variable star V480 Aql. Our V RI observations prove that this star belongs to classical Cepheids with the period of P = 19d.0016. We also...