Power spectra in extended tachyon cosmologies

Abstract

In the present work the power spectrum of a particular class of tachyon fields is compared with the one corresponding to a cosmological constant model. This is done for different barotropic indexes ${\gamma }_0$ and the background space time is assumed to be of the spatially flat Friedmann-Robertson-Walker type. The differential equation describing the perturbations is solved numerically and the power spectrum at the scale factor value $a=1$ is plotted for each case. The result is that the power spectrum of the standard tachyon field differs in many magnitude orders from the $\Lambda$CDM. However, the one with ${\gamma }_0=1.91$, which corresponds to a complementary tachyon field, coincides fairly well with the concordance model. Therefore, we conclude that the perturbed solutions constitute an effective method to distinguish between the different ${\gamma }_0$ values for the tachionization $\Lambda$CDM model and the fiducial model. The Statefinder parameters $\{r,s\}$, measuring the deviations of the analysed model from the concordance model, are also explicitly calculated. Our result suggest that, depending on the value of ${\gamma }_0$, these models can explain the observed expansion history or the perturbation power spectrum of the universe, but they may have problems in describing both features simultaneously.

7 pages, 7 figures, accepted for publication in General Relativity and Gravitation

References in corpus (10)

• Effects of Baryons and Dissipation on the Matter Power Spectrum
• Massive Neutrinos and the Non-linear Matter Power Spectrum
• Tachyon dark energy models: dynamics and constraints
• Observational constraints on patch inflation in noncommutative spacetime
• Tachyon Field in Intermediate Inflation
• Cosmological Scaling Solutions of Multiple Tachyon Fields with Inverse Square Potentials
• Matter power spectra in dynamical-Dark Energy cosmologies
• Primordial scalar perturbations in tachyonic power-law inflation
• Form invariance symmetry generates a large set of FRW cosmologies
• Extended tachyon field using form invariance symmetry

Cited by in corpus (2)

• Analysis cosmological tachyon and fermion model and observation data constraints
• Perturbations in some models of tachyonic inflation