Power spectrum in the Chaplygin gas model: tachyonic, fluid and scalar field representations

Abstract

The Chaplygin gas model, characterized by an equation of state of the type $p=-\frac{A}{\rho }$ emerges naturally from the Nambu-Goto action of string theory. This fluid representation can be recast under the form of a tachyonic field given by a Born-Infeld type Lagrangian. At the same time, the Chaplygin gas equation of state can be obtained from a self-interacting scalar field. We show that, from the point of view of the supernova type Ia data, the three representations (fluid, tachyonic, scalar field) lead to the same results. However, concerning the matter power spectra, while the fluid and tachyonic descriptions lead to exactly the same results, the self-interacting scalar field representation implies different statistical estimations for the parameters. In particular, the estimation for the dark matter density parameter in the fluid representation favors a universe dominated almost completely by dark matter, while in the self-interacting scalar field representation the prediction is very closed to that obtained in the $\Lambda$CDM model.

Latex file, 10 pages, 18 figures in EPS format

References in corpus (4)

• Gauge-invariant analysis of perturbations in Chaplygin gas unified models of dark matter and dark energy
• WMAP5 constraints on the unified model of dark energy and dark matter
• Tachyon cosmology, supernovae data and the Big Brake singularity
• Linear and non-Linear Instabilities in Unified Dark Energy Models

Cited by in corpus (11)

• Rastall cosmology
• Ruling out the Modified Chaplygin Gas Cosmologies
• Scalar models for the generalized Chaplygin gas and the structure formation constraints
• Critical behavior of AdS black holes surrounded by dark fluid with Chaplygin-like equation of state
• Topological AdS black holes surrounded by Chaplygin dark fluid: from stability to geometrothermodynamic analysis
• FRW type of cosmology with a Chaplygin gas
• Quintessential Phenomena in Higher Dimensional Space Time
• Black holes immersed in polytropic scalar field gas
• A note on observational signatures in superluminal unified dark matter models
• The $D$-dimensional charged AdS black holes solutions in polytropic dark energy from Barrow entropy
• Emergent Universe Scenario in the Modified Chaplygin gas : Towards an Exact Solution and Observational Constraints