Alberto Rozas-Fernández

Holographic kinetic k-essence model

Abstract We consider a connection between the holographic dark energy density and the kinetic k-essence energy density in a flat FRW universe. With the choice c ⩾ 1 , the holographic dark energy can be described by a kinetic k-essence scalar field in a certain way. In this Letter we show this kinetic k-essential description of the holographic dark energy with c ⩾ 1 and reconstruct the kinetic k-essence function F ( X ) .

Quantum cosmic models and thermodynamics

The current accelerating phase of the evolution of the universe is considered by constructing the most economical cosmic models that use just general relativity and some dominating quantum effects associated with the probabilistic description of quantum physics. Two such models are explicitly analyzed. They are based on the existence of a sub-quantum potential and correspond to a generalization of the spatially flat exponential model of de Sitter space. The thermodynamics of these two cosmic solutions is discussed, using the second principle as a guide to choose which among the two is more feasible. The paper also discusses the relativistic physics on which the models are based, their holographic description, some implications from the classical energy conditions and an interpretation of dark energy in terms of the entangled energy of the universe.

INTERACTING HOLOGRAPHIC TACHYON MODEL OF DARK ENERGY

We propose a holographic tachyon model of dark energy with interaction between the components of the dark sector. The correspondence between the tachyon field and the holographic dark energy densities allows the reconstruction of the potential and the dynamics of the tachyon scalar field in a flat Friedmann–Robertson–Walker universe. We show that this model can describe the observed accelerated expansion of our universe with a parameter space given by the most recent observational results.

A dark energy multiverse

We present cosmic solutions corresponding to universes filled with dark and phantom energy, all having a negative cosmological constant. All such solutions contain infinite singularities, successively and equally distributed along time, which can be either big bang/crunches or big rips singularities. Classically these solutions can be regarded as associated with multiverse scenarios, being those corresponding to phantom energy that may describe the current accelerating universe.

A gracious exit from the matter-dominated phase in a quantum cosmic phantom model

Abstract The most recent observational constraints coming from Planck, when combined with other cosmological data, provide evidence for a phantom scenario. In this work we consider a quantum cosmic phantom model where both the matter particles and scalar field are associated with quantum potentials which make the effective mass associated with the matter particles to vanish at the time of matter-radiation equality, resulting in a cosmic system where a matter dominance phase followed by an accelerating expansion is allowed.

INTERACTING NON-MINIMALLY COUPLED CANONICAL, PHANTOM AND QUINTOM MODELS OF HOLOGRAPHIC DARK ENERGY IN NON-FLAT UNIVERSE

Motivated by our recent work,72 we generalize this work to the interacting non-flat case. Therefore in this paper we deal with canonical, phantom and quintom models, with various fields that are non-minimally coupled to gravity, within the framework of interacting holographic dark energy. We employ the holographic model of interacting dark energy to obtain the equation of state for the holographic energy density in non-flat (closed) universe enclosed by the event horizon measured from the sphere of horizon named L.

Holographic interacting tachyon model

We propose an interacting holographic tachyon model of dark energy. A correspondence between the tachyon energy density and the interacting holographic dark energy is established. As a result, we reconstruct the potential of the interacting holographic tachyon field and the dynamics of the tachyon field, in a flat Friedmann-Robertson-Walker background. We show that the evolution of the universe for −1 < w < 0 can be completely described by the resulting interacting tachyon model.

Holographic kinetic k‐essence cosmologies

We consider a connection between the holographic dark energy density and the kinetic k‐essence energy density in a flat FRW universe. We show this kinetic k‐essential description of the holographic dark energy with c⩾1 and reconstruct the kinetic k‐essence function F(X).