Please use this identifier to cite or link to this item:
https://repositorio.ufba.br/handle/ri/15983
metadata.dc.type: | Artigo de Periódico |
Title: | Non-adiabatic Chaplygin gas |
Other Titles: | Physics Letters B |
Authors: | Borges, H. A. Carneiro, Saulo Fabris, J. C. Zimdahl, W. |
metadata.dc.creator: | Borges, H. A. Carneiro, Saulo Fabris, J. C. Zimdahl, W. |
Abstract: | The split of a generalised Chaplygin gas with an equation of state p=−A/ραp=−A/ρα into an interacting mixture of pressureless matter and a dark-energy component with equation of state pΛ=−ρΛpΛ=−ρΛ implies the existence of non-adiabatic pressure perturbations. We demonstrate that the square of the effective (non-adiabatic) sound speed cscs of the medium is proportional to the ratio of the perturbations of the dark energy to those of the dark matter. Since, as demonstrated explicitly for the particular case α=−1/2α=−1/2, dark-energy perturbations are negligible compared with dark-matter perturbations on scales that are relevant for structure formation, we find View the MathML source|cs2|≪1. Consequently, there are no oscillations or instabilities which have plagued previous adiabatic Chaplygin-gas models. |
metadata.dc.rights: | Acesso Aberto |
URI: | http://repositorio.ufba.br/ri/handle/ri/15983 |
Issue Date: | 2013 |
Appears in Collections: | Artigo Publicado em Periódico (FIS) |
Files in This Item:
File | Description | Size | Format | |
---|---|---|---|---|
1-s2.0-S0370269313008381-main.pdf | 253,14 kB | Adobe PDF | View/Open |
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.