Are dark energy models with variable EoS parameter w compatible with the late inhomogeneous Universe?

Journal Article · Wed Jul 01 04:00:00 EDT 2015 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2015/07/038· OSTI ID:22525637

Akarsu, Özgür ^[1]; Bouhmadi-López, Mariam ^[2]; Brilenkov, Maxim; Brilenkov, Ruslan ^[3]; Eingorn, Maxim ^[4]; Zhuk, Alexander ^[5]

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1. Department of Physics, Koç University, 34450 Sarıyer, İstanbul (Turkey)
2. Departamento de Física, Universidade da Beira Interior, 6200 Covilhã (Portugal)
3. Department of Theoretical Physics, Odessa National University, Street Dvoryanskaya 2, Odessa 65082 (Ukraine)
4. North Carolina Central University, CREST and NASA Research Centers, Fayetteville st. 1801, Durham, North Carolina 27707 (United States)
5. Astronomical Observatory, Odessa National University, Street Dvoryanskaya 2, Odessa 65082 (Ukraine)

We study the late-time evolution of the Universe where dark energy (DE) is presented by a barotropic fluid on top of cold dark matter (CDM) . We also take into account the radiation content of the Universe. Here by the late stage of the evolution we refer to the epoch where CDM is already clustered into inhomogeneously distributed discrete structures (galaxies, groups and clusters of galaxies). Under this condition the mechanical approach is an adequate tool to study the Universe deep inside the cell of uniformity. More precisely, we study scalar perturbations of the FLRW metric due to inhomogeneities of CDM as well as fluctuations of radiation and DE. For an arbitrary equation of state for DE we obtain a system of equations for the scalar perturbations within the mechanical approach. First, in the case of a constant DE equation of state parameter w, we demonstrate that our method singles out the cosmological constant as the only viable dark energy candidate. Then, we apply our approach to variable equation of state parameters in the form of three different linear parametrizations of w, e.g., the Chevallier-Polarski-Linder perfect fluid model. We conclude that all these models are incompatible with the theory of scalar perturbations in the late Universe.

• OSTI ID: 22525637
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 07 Vol. 2015; ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COSMOLOGICAL CONSTANT
DISTURBANCES
EQUATIONS OF STATE
FLUCTUATIONS
FLUIDS
GALACTIC EVOLUTION
GALAXIES
GALAXY CLUSTERS
IDEAL FLOW
METRICS
NONLUMINOUS MATTER
SCALARS
UNIVERSE