Examinando por Autor "Lepe, Samuel"

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  • Miniatura
    Ítem
    Challenging matter creation models in the phantom divide
    (American Physical Society, 2020) Cardenas, Victor H.; Cruz, Miguel; Lepe, Samuel; Nojiri, Shin’ichi; Odintsov, Sergei D.
    We perform a study both statistical and theoretical for cosmological models of matter creation and their ability to describe effective phantom models of dark energy. Such models are beyond the ΛCDM model since the resulting cosmic expansion is not adiabatic. In fact, we show that this approach exhibits transient phantom/quintessence scenarios at present time and tends to the standard cosmological model at some stage of the cosmic evolution. We discuss some generalities of the thermodynamics properties for this type of cosmological model; we emphasize on the behavior of the temperature associated to dark matter, which keeps positive along cosmic evolution together with the entropy. The enrichment of this type of model by means of the incorporation of cosmological constant and dissipative effects in the fluid description to explore their cosmological consequences in the expansion of the Universe is considered. Finally, a generalization for the matter production rate as an inhomogeneous expression of the Hubble parameter and its derivatives is discussed; as in all the cases examined, such election leads to an effective phantom/quintessence behavior
  • Miniatura
    Ítem
    Interacting dark matter and cosmic acceleration
    (EDP Sciences, 2020) Cardenas, Victor H.; Lepe, Samuel
    We study the effect of an explicit interaction between two scalar fields components describing dark matter in the context of a recent proposal framework for interaction. We find that, even assuming a very small coupling, it is sufficient to explain the observational effects of a cosmological constant, and also overcome the problems of the Λ CDM model without assuming an exotic dark energy.