Now showing items 1-20 of 42

  • An extended matter bounce scenario: current status and challenges 

    Haro Cases, Jaume; Cai, Yi-Fu (2015-08-01)
    Article
    Open Access
    As an alternative to the paradigm of slow roll inflation, we propose an extended scenario of the matter bounce cosmology in which the Universe has experienced a quasi-matter contracting phase with a variable background ...
  • ANTARES constrains a blazar origin of two IceCube PeV neutrino events 

    Adrian Martinez, Silvia; Albert, Andreas; André, Michel (2015-04-01)
    Article
    Open Access
    Context. The source(s) of the neutrino excess reported by the IceCube Collaboration is unknown. The TANAMI Collaboration recently reported on the multiwavelength emission of six bright, variable blazars which are positionally ...
  • Bouncing cosmologies in geometries with positively curved spatial sections 

    Haro Cases, Jaume (Elsevier, 2016-09-10)
    Article
    Open Access
    Background bouncing cosmologies, driven by a single scalar field, having a quasi-matter domination period during the contracting phase, i.e., depicting the so-called Matter Bounce Scenario, are reconstructed for cosmologies ...
  • Bouncing cosmologies via modified gravity in the ADM formalism: Application to loop quantum cosmology 

    Haro Cases, Jaume; Amorós Torrent, Jaume (American Physical Society (APS), 2018-03-15)
    Article
    Open Access
    We consider the Arnowitt-Deser-Misner formalism as a tool to build bouncing cosmologies. In this approach, the foliation of the spacetime has to be fixed in order to go beyond general relativity modifying the gravitational ...
  • Bouncing loop quantum cosmology from F(T) gravity 

    Amorós Torrent, Jaume; Haro Cases, Jaume; Odintsov, Sergei D. (2013-05)
    Article
    Open Access
    The big bang singularity could be understood as a breakdown of Einstein’s general relativity at very high energies. By adopting this viewpoint, other theories that implement Einstein cosmology at high energies might solve ...
  • Bulk viscous quintessential inflation 

    Haro Cases, Jaume; Pan, Supriya (2018-04-01)
    Article
    Open Access
    In a spatially-flat Friedmann–Lemaître–Robertson–Walker universe, the incorporation of bulk viscous process in general relativity leads to an appearance of a nonsingular background of the universe that both at early and ...
  • Charge-induced force noise on free-falling test masses: results from LISA pathfinder 

    Armano, M.; Audley, H.; Auger, G.; Baird, J.; Binetruy, P.; Ramos Castro, Juan José (2017-04-26)
    Article
    Open Access
    We report on electrostatic measurements made on board the European Space Agency mission LISA Pathfinder. Detailed measurements of the charge-induced electrostatic forces exerted on free-falling test masses (TMs) inside the ...
  • Cosmologia: passat, present i futur de l'univers 

    Aragoneses Aguado, Andrés (2010-05-04)
    Audiovisual
    Open Access
    La Cosmologia se centra en l'estudi del passat, present i futur de l'univers. Des d'antany respón a aquestes preguntes, ha estat una de les grans motivacions de la humanitat. Quina és la destinació de l'Univers?. La resposta....
  • Cosmología y cosmogonía 

    Barceló Garcia, Miquel (2007-04)
    Article
    Open Access
  • Cosmological perturbations in a class of fully covariant modified theories: application to models with the same background as standard LQC 

    Haro Cases, Jaume; Aresté Saló, Llibert; Elizalde, Emilio (Springer, 2018-09-01)
    Article
    Open Access
    Bouncing cosmologies are obtained by adding to the Einstein–Hilbert action a term of the form -g---vf(¿), with ¿ a scalar depending on the Hubble parameter only, not on its derivatives, and which is here shown to arise ...
  • Dark energy and thermonuclear supernovae 

    Domínguez, Inmaculada; Bravo Guil, Eduardo; Piersanti, L.; Tornambé, A.; Straniero, O.; Höfflich, P. (Ulla, A.; Manteiga, M. / Real Sociedad Española de Física, 2007)
    Conference report
    Open Access
    Nowadays it is widely accepted that the current Universe is dominated by dark energy and exotic matter, the so called StandardModel of Cosmoloy or _CDM model. All the available data (Thermonuclear Supernovae, Cosmic Microwave ...
  • Design of an expanding cosmological background for the moving punctures approach to numerical relativity 

    Manyer Fuertes, Jordi (Universitat Politècnica de Catalunya, 2019-05-31)
    Bachelor thesis
    Open Access
    Covenantee:  Center for Relativistic Astrophysics
    Gravitational waves astronomy is a new field ushered in by the first detection of a par of merging black holes. Numerical relativity is the only tool capable of solving Einstein’s equations for the the dynamics and resulting ...
  • Different reheating mechanisms in quintessence inflation 

    Haro Cases, Jaume (American Physical Society (APS), 2019-02-11)
    Article
    Open Access
    Different well-known ways to reheat the Universe, such as instant preheating, the creation of particles nearly or conformally coupled with gravity, or from the decay of products of a curvaton field, are revisited and ...
  • Evolution and dynamics of a matter creation model 

    Pan, Supriya; Haro Cases, Jaume; Paliathanasis, A.; Slagter, R.J. (2016-05-01)
    Article
    Open Access
    In a flat Friedmann–Lemaître–Robertson–Walker (FLRW) geometry, we consider the expansion of the universe powered by the gravitationally induced ‘adiabatic’ matter creation. To demonstrate how matter creation works well ...
  • Gravitational Particle Production in Massive Chaotic Inflation and the Moduli Problem 

    Haro Cases, Jaume; Elizalde, Emilio (2012-02)
    Article
    Restricted access - publisher's policy
    Particle production from vacuum fluctuations during inflation is briefly revisited. The moduli problem occurring with light particles produced at the end of inflation is addressed, namely the fact that some results are in ...
  • Homothetic motions and Newtonian cosmology 

    Jaen Herbera, Javier; Molina Compte, Alfred (2014-05-07)
    Article
    Restricted access - publisher's policy
    We construct a homothetic covariant Newtonian gravitation theory which unifies inertial homothetic forces and gravitational fields. This is achieved through an equivalence principle based on a local homothetic frame of ...
  • How can holonomy corrections be introduced in f(R) gravity? 

    Haro Cases, Jaume (2014-07-08)
    Article
    Open Access
    We study the introduction of holonomy corrections in f(R) gravity. We will show that there are infinitely many ways, as many as canonical transformations, to introduce this kind of corrections, depending on the canonical ...
  • La eterna historia 

    Barceló Garcia, Miquel (1995-12)
    Article
    Open Access
  • Limiting curvature mimetic gravity and its relation to Loop Quantum Cosmology 

    Haro Cases, Jaume; Aresté Saló, Llibert; Pan, Supriya (2019-04-01)
    Article
    Restricted access - publisher's policy
    Considering as usual that the underlying geometry of our universe is well described by the spatially flat Friedmann–Lemaître–Robertson–Walker line element, we review how the background of holonomy corrected Loop Quantum ...
  • Modelos cosmológicos en el marco de la teoría general de la relatividad 

    Ribera Manzano, Pablo (Universitat Politècnica de Catalunya, 2016-06-29)
    Bachelor thesis
    Open Access
    Detailed work about relativistic cosmology: exposition of the principles and postulates, description of the geometry of spacetime and its matter contents, Hubble's law from a relativistic point of view, analysis of the ...