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  • A varying dark energy effective speed of sound parameter in the phantom Universe
    Publication . Albarran, Imanol; Bouhmadi Lopez, Mariam; Marto, João
    We analyse the phenomenological effects of a varying Dark Energy (DE) effective speed of sound parameter, c2sd, 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, fσ8 growth rate and forecast the current matter power spectrum. We vary the c2sd parameter in the interval [0, 1] and compute the relative deviation with respect c2sd=1. In addition, we analyse the effect of gravitational potential sign flip that occurs at very large scale factors as compared with the current one.
    2021-09-09Journal article Open access Show more