Covariant holography of a tachyonic accelerating universe

We apply the holographic principle to a flat dark energy dominated Friedmann-Robertson-Walker spacetime filled with a tachyon scalar field with constant equation of state $w=p/\rho$, both for $w>-1$ and $w<-1$. By using a geometrical covariant procedure, which allows the construction of holographic hypersurfaces, we have obtained for each case the position of the preferred screen and have then compared these with those obtained by using the holographic dark energy model with the future event horizon as the infrared cutoff. In the phantom scenario, one of the two obtained holographic screens is placed on the big rip hypersurface, both for the covariant holographic formalism and the holographic phantom model. It is also analyzed whether the existence of these preferred screens allows a mathematically consistent formulation of fundamental theories based on the existence of a S matrix at infinite distances.Comment: 7 pages, 4 figures, one reference added, matches published versio

K-essential covariant holography

The holographic principle is applied to a flat Friedmann-Robertson-Walker space-time dominated by dark energy when this is due to the presence of a k-essence scalar field, both for dark energy and phantom scenarios. In this framework, a geometrical covariant approach permits the construction of holographic hypersurfaces. The resulting covariant preferred screens, both for phantom and non-phantom regions, are then compared with those obtained by using the holographic dark energy model with the future event horizon as the infrared cut-off. In the phantom case, one of the two obtained holographic screens is placed on the big rip hypersurface, both for the covariant holographic formalism and the holographic phantom model. It is also analysed whether this covariant formalism allows a mathematically consistent formulation of fundamental theories based on the existence of a S-matrix at infinite distances.Comment: 14 pages, 6 figures. Accepted for publication in General Relativity and Gravitation. arXiv admin note: substantial text overlap with arXiv:1407.842

Phenomenology of Unified Dark Matter models with fast transition

A fast transition between a standard matter-like era and a late $\Lambda$CDM-like epoch generated by a single Unified Dark Matter component can explain the observed acceleration of the Universe. UDM models with a fast transition should be clearly distinguishable from $\Lambda$CDM (and alternatives) through observations. Here we focus on a particularly simple model and analyse its viability by studying features of the background model and properties of the adiabatic UDM perturbations.Comment: 4 pages, 1 figure, Proceedings of the Spanish Relativity Meeting ERE2012, University of Minho, Guimar\~aes, Portugal, September 3-7, 201

Cosmic models and holography

Tesis doctoral inédita. Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Física Teóric

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.Comment: 7 pages, 8 figures, accepted for publication in IJMP

Interacting non-minimally coupled canonical, phantom and quintom models of holographic dark energy in non-flat universe

Motivated by our recent work \cite{set1}, we generalize this work to the interacting non-flat case. Therefore in this paper we deal with canonical, phantom and quintom models, with the various fields being 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 $L$.Comment: 18 pages, 3 figures. Accepted for publication in IJMPD (2010

Planeamiento estratégico de la naranja

El presente trabajo propone un plan estratégico para la industria de la naranja en el Perú, con la finalidad de consolidarlo como el segundo exportador de naranjas de Sudamérica para el año 2023, logrando una posición de liderazgo en los mercados de Europa y América del Norte, manteniendo un marco de responsabilidad social, y cuidando el medioambiente. A la fecha, el Perú consume toda su producción de naranja, por lo que la propuesta contempla aprovechar su posición geográfica de contraestación a los grandes consumidores, aumentar la producción y la productividad, y mejorar la calidad de sus productos para ingresar a los grandes mercados que permiten una mayor rentabilidad, logrando así mejoras económicas para todos los participantes que intervienen en el proceso. El presente instrumento se ha realizado tomando como marco conceptual el modelo secuencial, en donde se han identificados los factores críticos para el desarrollo del sector naranja estableciendo objetivos a largo plazo y estrategias que se deben implementar para alcanzarlasThis project proposes a strategic plan for the orange industry in Peru with the purpose of consolidating the country the second exporter of oranges in South America in 2023, by achieving a leadership position in the European and North American markets and maintaining a framework of social responsibility while protecting the environment. Nowadays, Peru consumes its own orange production, that’s why this proposal contemplate to take advantage of its counterseason geographical position to the biggest consumers, increase production and productivity and improve its products quality for entering to the most important and biggest markets that allow a better profitability, thus achieving economic improvements for the participants involved in this process. This document was executed taking as conceptual framework the Sequential Model, where some critical factors were identified for the development of the orange sector, establishing long term objectives and strategies that should be implemented for meet themTesi

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/crunchs or big rips singularities. Classicaly these solutions can be regarded as associated with multiverse scenarios, being those corresponding to phantom energy that may describe the current accelerating universe

Quantum cosmic models and thermodynamics

The current accelerating phase of the evolution of the universe is considered by constructing most economical cosmic models that use just general relativity and some dominating quantum effects associated with the probabilistic description of quantum physics. Two of 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.Comment: 15 pages, 1 figure, accepted for publication in Class. Quantum Gra