Properties and uncertainties of scalar field models of dark energy with barotropic equation of state

Abstract

The dynamics of expansion and large scale structure formation in the multicomponent Universe with dark energy modeled by the minimally coupled scalar field with generalized linear barotropic equation of state (EoS) are analyzed. It is shown that the past dynamics of expansion and future of the Universe -- eternal accelerated expansion or turnaround and collapse -- are completely defined by the current energy density of a scalar field and relation between its current and early EoS parameters. The clustering properties of such models of dark energy and their imprints in the power spectrum of matter density perturbations depend on the same relation and, additionally, on the "effective sound speed" of a scalar field, defined by its Lagrangian. It is concluded that such scalar fields with different values of these parameters are distinguishable in principle. This gives the possibility to constrain them by confronting the theoretical predictions with the corresponding observational data. For that we have used the 7-year WMAP data on CMB anisotropies, the Union2 dataset on Supernovae Ia and SDSS DR7 data on luminous red galaxies (LRG) space distribution. Using the Markov Chain Monte Carlo technique the marginalized posterior and mean likelihood distributions are computed for the scalar fields with two different Lagrangians: Klein-Gordon and Dirac-Born-Infeld ones. The properties of such scalar field models of dark energy with best fitting parameters and uncertainties of their determination are also analyzed in the paper.

17 pages, 9 figures, 2 tables, minor corrections, references added, accepted for publication in Phys. Rev. D

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Cited by in corpus (6)

• Sound speed of scalar field dark energy: weak effects and large uncertainties
• Dynamics of dark energy in the gravitational fields of matter inhomogeneities
• Dynamics of expansion of the Universe in the models with non-minimally coupled dark energy
• Evolution of cosmological perturbations in the models with interacting dynamical dark energy
• Scalar field models of dark energy with barotropic equation of state: properties and observational constraints from different datasets
• Constraints on Multicomponent Dark Energy from Cosmological Observations