Regular Article - Theoretical Physics
A varying dark energy effective speed of sound parameter in the phantom Universe
Departamento de Física, Universidade da Beira Interior, Rua Marquês D’Ávila e Bolama, 6200-001, Covilhã, Portugal
2 Centro de Matemática e Aplicações da Universidade da Beira Interior, Rua Marquês D’Ávila e Bolama, 6200-001, Covilhã, Portugal
3 Department of Physics, University of the Basque Country UPV/EHU, P.O. Box 644, 48080, Bilbao, Spain
4 IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain
Accepted: 10 August 2021
Published online: 9 September 2021
We analyse the phenomenological effects of a varying Dark Energy (DE) effective speed of sound parameter, , on the cosmological perturbations of three phantom DE models. Each of these models induce a particular abrupt future event known as Big Rip (BR), Little Rip (LR), and Little Sibling of the Big Rip (LSBR). In this class of abrupt events, all the bound structures in the Universe would be ripped apart at a finite cosmic time. We compute the evolution of the perturbations, growth rate and forecast the current matter power spectrum. We vary the parameter in the interval [0, 1] and compute the relative deviation with respect . In addition, we analyse the effect of gravitational potential sign flip that occurs at very large scale factors as compared with the current one.
© The Author(s) 2021
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
Funded by SCOAP3