We explore the possibility that a scalar field with appropriate Lagrangian can mimic a perfect fluid with an affine barotropic equation of state. The latter can be thought of as a generic cosmological dark component evolving as an effective cosmological constant plus a generalized dark matter. As such, it can be used as a simple, phenomenological model for either dark energy or unified dark matter. Furthermore, it can approximate (up to first order in the energy density) any barotropic dark fluid with arbitrary equation of state. We find that two kinds of Lagrangians for the scalar field can reproduce the desired behaviour: a quintessence-like with a hyperbolic potential, or a purely kinetic k-essence one. We discuss the behaviour of these two classes of models from the point of view of the cosmological background, and give some hints on their possible clustering properties.

Quercellini, C., Bruni, M., & Balbi, A. (2007). Affine equation of state from quintessence and k-essence fields. CLASSICAL AND QUANTUM GRAVITY, 24(22), 5413-5425 [10.1088/0264-9381/24/22/006].

Affine equation of state from quintessence and k-essence fields

BALBI, AMEDEO
2007

Abstract

We explore the possibility that a scalar field with appropriate Lagrangian can mimic a perfect fluid with an affine barotropic equation of state. The latter can be thought of as a generic cosmological dark component evolving as an effective cosmological constant plus a generalized dark matter. As such, it can be used as a simple, phenomenological model for either dark energy or unified dark matter. Furthermore, it can approximate (up to first order in the energy density) any barotropic dark fluid with arbitrary equation of state. We find that two kinds of Lagrangians for the scalar field can reproduce the desired behaviour: a quintessence-like with a hyperbolic potential, or a purely kinetic k-essence one. We discuss the behaviour of these two classes of models from the point of view of the cosmological background, and give some hints on their possible clustering properties.
Pubblicato
Rilevanza internazionale
Articolo
Sì, ma tipo non specificato
Settore FIS/05 - Astronomia e Astrofisica
English
DARK ENERGY; SCALAR FIELD; MATTER; COSMOLOGY; SUPERNOVAE; INFLATION; DYNAMICS; BEHAVIOR; MODELS
Quercellini, C., Bruni, M., & Balbi, A. (2007). Affine equation of state from quintessence and k-essence fields. CLASSICAL AND QUANTUM GRAVITY, 24(22), 5413-5425 [10.1088/0264-9381/24/22/006].
Quercellini, C; Bruni, M; Balbi, A
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2108/35822
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