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...

Descripción completa

Guardado en:
Detalles Bibliográficos
Publicado: 2015
Materias:
Cosmology perturbations
Extended tachyon fields
Power spectrum
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00017701_v47_n10_p_SanchezG
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 paper:paper_00017701_v47_n10_p_SanchezG
record_format dspace
spelling paper:paper_00017701_v47_n10_p_SanchezG2023-06-08T14:21:39Z Power spectra in extended tachyon cosmologies 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. 2015 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00017701_v47_n10_p_SanchezG 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
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.
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
publishDate 2015
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00017701_v47_n10_p_SanchezG
http://hdl.handle.net/20.500.12110/paper_00017701_v47_n10_p_SanchezG
_version_ 1768543397125029888

Ejemplares similares