Francisco Peña

Dissipative generalized Chaplygin gas as phantom dark energy

Abstract The generalized Chaplygin gas, characterized by the equation of state p = − A / ρ α , has been considered as a model for dark energy due to its dark-energy-like evolution at late times. When dissipative processes are taken into account, within the framework of the standard Eckart theory of relativistic irreversible thermodynamics, cosmological analytical solutions are found. Using the truncated causal version of the Israel–Stewart formalism, a suitable model was constructed which crosses the w = − 1 barrier. The future-singularities encountered in both approaches are of a new type, and not included in the classification presented by Nojiri and Odintsov [S. Nojiri, S.D. Odintsov, Phys. Rev. D 72 (2005) 023003].

Dark energy interacting with two fluids

A cosmological model of dark energy interacting with dark matter and another general component of the universe is investigated. We found general constraints on these models imposing an accelerated expansion. The same is also studied in the case for holographic dark energy.

Scalar field scattering by a Lifshitz black hole under a non-minimal coupling

We study the behavior of a scalar field under a z = 3 Lifshitz black hole background, in a way that is non-minimally coupled to the gravitational field . A general analytical solution is obtained along with two sets of quasinormal modes associated to different boundary conditions that can be imposed on the scalar field, non-minimal coupling parameter appears explicitly on these solutions. Stability of quasinormal modes can be studied and ensured for both cases. Also, the reflection and absorption coe ffi cients are calculated, as well as the absorption cross secti on which features an interesting behavior because of being attenuated by terms strongly dependant on the non-minimal coupling. By a suitable change of variables a soliton solution can also be obtained and the stability of the quasinormal modes are studied and ensured.

Randall–Sundrum model with λ<0 and bulk brane viscosity

Abstract We study the effect of the inclusion of bulk brane viscosity on brane world (BW) cosmology in the framework of the Eckarts theory, we focus in the Randall–Sundrum model with negative tension on the brane.

Crossing the phantom divide with Ricci-like holographic dark energy

In this work we study the dark energy problem by adopting an holographic model proposed recently in the literature. In this model there has been postulated an energy density ρ∼R, where R is the Ricci scalar curvature. Under this consideration, we have obtained a cosmological scenario which arises from considering two non-interacting fluids along the lines of a reasonable Ansatz for the cosmic coincidence parameter. We have adjusted the involved parameters in the model according to the observational data, showing that the equation of state for the dark energy exhibits a cross through the −1 barrier. Additionally, we have found a disagreement of these parameters in comparison with a scalar field theory approach.

Holographic dark energy interacting with dark matter in a closed Universe

Abstract A cosmological model of an holographic dark energy interacting with dark matter throughout a decaying term of the form Q = 3 ( λ 1 ρ DE + λ 2 ρ m ) H is investigated. General constraint on the parameters of the model are found when accelerated expansion is imposed and we found a phantom scenario, without any reference to a specific equation of state for the dark energy. The behavior of equation of state for dark energy is also discussed.

Interacting Ricci-like holographic dark energy

In a flat Friedmann–Lemaitre–Robertson–Walker background, a scheme of dark matter–dark energy interaction is studied considering a holographic Ricci-like model for the dark energy. Without giving a priori some specific model for the interaction function, we show that this function can experience a change of sign during the cosmic evolution. The parameters involved in the holographic model are adjusted with Supernova data and we obtained results compatible with the observable universe.

Chiral-symmetry breaking in pseudoquantum electrodynamics at finite temperature

We use the Schwinger-Dyson equations in the presence of a thermal bath, in order to study chiral-symmetry breaking in a system of massless Dirac fermions interacting through pseudo quantum electrodynamics, in (

DGP cosmological model with generalized Ricci dark energy

2+1

Chern-Simons terms in Lifshitz like quantum electrodynamics

) dimensions. We show that there is a critical temperature