Power spectra in extended tachyon cosmologies

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 (Formula presented.) and the background space time is assumed to be of the spatially flat Friedmann–Ro...

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Autores principales:	Sánchez G, I.E., Santillán, O.P.
Formato:	JOUR
Materias:	Cosmology perturbations Extended tachyon fields Power spectrum
Acceso en línea:	http://hdl.handle.net/20.500.12110/paper_00017701_v47_n10_p_SanchezG
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	todo:paper_00017701_v47_n10_p_SanchezG
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spelling	todo:paper_00017701_v47_n10_p_SanchezG2023-10-03T13:52:09Z Power spectra in extended tachyon cosmologies Sánchez G, I.E. Santillán, O.P. Cosmology perturbations Extended tachyon fields Power spectrum 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 (Formula presented.) 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 (Formula presented.) is plotted for each case. The result is that the power spectrum of the standard tachyon field differs in many magnitude orders from the (Formula presented.)CDM. However, the one with(Formula presented.), 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 (Formula presented.) values for the tachionization (Formula presented.)CDM model and the fiducial model. The Statefinder parameters (Formula presented.), measuring the deviations of the analysed model from the concordance model, are also explicitly calculated. Our result suggest that, depending on the value of (Formula presented.), 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. © 2015, Springer Science+Business Media New York. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00017701_v47_n10_p_SanchezG
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Cosmology perturbations Extended tachyon fields Power spectrum
spellingShingle	Cosmology perturbations Extended tachyon fields Power spectrum Sánchez G, I.E. Santillán, O.P. Power spectra in extended tachyon cosmologies
topic_facet	Cosmology perturbations Extended tachyon fields Power spectrum
description	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 (Formula presented.) 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 (Formula presented.) is plotted for each case. The result is that the power spectrum of the standard tachyon field differs in many magnitude orders from the (Formula presented.)CDM. However, the one with(Formula presented.), 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 (Formula presented.) values for the tachionization (Formula presented.)CDM model and the fiducial model. The Statefinder parameters (Formula presented.), measuring the deviations of the analysed model from the concordance model, are also explicitly calculated. Our result suggest that, depending on the value of (Formula presented.), 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. © 2015, Springer Science+Business Media New York.
format	JOUR
author	Sánchez G, I.E. Santillán, O.P.
author_facet	Sánchez G, I.E. Santillán, O.P.
author_sort	Sánchez G, I.E.
title	Power spectra in extended tachyon cosmologies
title_short	Power spectra in extended tachyon cosmologies
title_full	Power spectra in extended tachyon cosmologies
title_fullStr	Power spectra in extended tachyon cosmologies
title_full_unstemmed	Power spectra in extended tachyon cosmologies
title_sort	power spectra in extended tachyon cosmologies
url	http://hdl.handle.net/20.500.12110/paper_00017701_v47_n10_p_SanchezG
work_keys_str_mv	AT sanchezgie powerspectrainextendedtachyoncosmologies AT santillanop powerspectrainextendedtachyoncosmologies
_version_	1807316397816020992

Power spectra in extended tachyon cosmologies

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