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Author |
Beltran Jimenez, J.; Heisenberg, L.; Olmo, G.J. |
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Title |
Infrared lessons for ultraviolet gravity: the case of massive gravity and Born-lnfeld |
Type |
Journal Article |
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Year |
2014 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
11 |
Issue  |
11 |
Pages |
004 - 26pp |
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Keywords |
modified gravity; alternatives to inflation; gravity |
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Abstract |
We generalize the ultraviolet sector of gravitation via a Born-Infeld action using lessons from massive gravity. The theory contains all of the elementary symmetric polynomials and is treated in the Palatini formalism. We show how the connection can be solved algebraically to be the Levi-Civita connection of an effective metric. The non-linearity of the algebraic equations yields several branches, one of which always reduces to General Relativity at low curvatures. We explore in detail a minimal version of the theory, for which we study solutions in the presence of a perfect fluid with special attention to the cosmological evolution. In vacuum we recover Ricci-flat solutions, but also an additional physical solution corresponding to an Einstein space. The existence of two physical branches remains for non-vacuum solutions and, in addition, the branch that connects to the Einstein space in vacuum is not very sensitive to the specific value of the energy density. For the branch that connects to the General Relativity limit we generically find three behaviours for the Hubble function depending on the equation of state of the fluid, namely: either there is a maximum value for the energy density that connects continuously with vacuum, or the energy density can be arbitrarily large but the Hubble function saturates and remains constant at high energy densities, or the energy density is unbounded and the Hubble function grows faster than in General Relativity. The second case is particularly interesting because it could offer an interesting inflationary epoch even in the presence of a dust component. Finally, we discuss the possibility of avoiding certain types of singularities within the minimal model. |
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Address |
[Jimenez, Jose Beltran] Univ Louvain, Ctr Cosmol Particle Phys & Phenomenol, Inst Math & Phys, B-1348 Louvain La Neuve, Belgium, Email: jose.beltran@uclouvain.be; |
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Iop Publishing Ltd |
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English |
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ISSN |
1475-7516 |
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Conference |
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Notes |
WOS:000346105300004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2039 |
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Author |
Beltran Jimenez, J.; Heisenberg, L.; Olmo, G.J.; Ringeval, C. |
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Title |
Cascading dust inflation in Born-lnfeld gravity |
Type |
Journal Article |
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Year |
2015 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
11 |
Issue |
11 |
Pages |
046 - 30pp |
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Keywords |
modified gravity; inflation |
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Abstract |
In the framework of Born-Infeld inspired gravity theories, which deviates from General Relativity (GR) in the high curvature regime, we discuss the viability of Cosmic Inflation without scalar fields. For energy densities higher than the new mass scale of the theory, a gravitating (lust component is shown to generically induce an accelerated expansion of the Universe. Within such a simple scenario, inflation gracefiffly exits when the CR regime is recovered, but the Universe would remain matter dominated. In order to implement a reheating era after inflation, we then consider inflation to be driven by a mixture of unstable dust species decaying into radiation. Because the speed of sound gravitates within the BornInfeld model under consideration, our scenario ends up being predictive on various open questions of the inflationary paradigm. The total number of e-folds of acceleration is given by the lifetime of the unstable dust components and is related to the duration of reheating. As a result, inflation does not last much longer than the number of e-folds of deceleration allowing a small spatial curvature and large scale deviations to isotropy to be observable today. Energy densities are self-regulated as inflation can only start for a total energy density less than a threshold value, again related to the species' lifetime. Above this threshold, the Universe may bc nee thereby avoiding a singularity. Another distinctive feature is that the accelerated expansion is of the superinflationary ldnd, namely the first Hubble flow function is negative. We show however that the tensor modes are never excited and the tensor-to-scalar ratio is always vanishing, independently of the energy scale of inflation. |
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Address |
[Jimenez, Jose Beltran] Aix Marseille Univ, Ctr Phys Theor, UMR 7332, F-13288 Marseille, France, Email: jose.beltran@cpt.univ-mrs.fr; |
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Publisher |
Iop Publishing Ltd |
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English |
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ISSN |
1475-7516 |
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Expedition |
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Conference |
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Notes |
WOS:000365821200047 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2478 |
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Author |
Valle, J.W.F. |
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Title |
Status and implications of neutrino masses: a brief panorama |
Type |
Journal Article |
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Year |
2015 |
Publication |
International Journal of Modern Physics A |
Abbreviated Journal |
Int. J. Mod. Phys. A |
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Volume |
30 |
Issue |
13 |
Pages |
1530034 - 13pp |
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Keywords |
Neutrino mixing and oscillations; seesaw mechanism; quark-lepton unification; flavor symmetry; electroweak symmetry breaking; neutrinoless double beta decay; dark matter; inflation |
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Abstract |
With the historic discovery of the Higgs boson our picutre of particle physics would have been complete were it nor for the neutrino sector and cosmology. I briefly discuss the role of neutrino masses and mixing upon gauge coupling unification, electroweak breaking and the flavor sector. Time is ripe for new discoveries such as leptonic CP violation, charged lepton flavor violation and neutrinoless double beta decay. Neutrinos could also play a role is elucidating the nature of dark matter and cosmic inflation. |
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Address |
Univ Valencia, CSIC, Inst Fis Corpuscular, E-46980 Valencia, Spain |
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Publisher |
World Scientific Publ Co Pte Ltd |
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English |
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Series Volume |
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Edition |
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ISSN |
0217-751x |
ISBN |
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Notes |
WOS:000353955400002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
2211 |
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Author |
Barenboim, G.; Park, W.I. |
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Title |
New- vs. chaotic- inflations |
Type |
Journal Article |
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Year |
2016 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
02 |
Issue |
2 |
Pages |
061 - 20pp |
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Keywords |
inflation; physics of the early universe; cosmology of theories beyond the SM |
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Abstract |
We show that “spiralized” models of new-inflation can be experimentally identified mostly by their positive spectral running in direct contrast with most chaotic-inflation models which have negative runnings typically in the range of O(10(-4)-10(-3)). |
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Address |
[Barenboim, Gabriela; Park, Wan-Il] Univ Valencia, Dept Fis Teor, CSIC, E-46100 Burjassot, Spain, Email: Gabriela.Barenboim@uv.es; |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1475-7516 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000372467600062 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
2589 |
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Author |
Escudero, M.; Ramirez, H.; Boubekeur, L.; Giusarma, E.; Mena, O. |
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Title |
The present and future of the most favoured inflationary models after Planck 2015 |
Type |
Journal Article |
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Year |
2016 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
02 |
Issue |
2 |
Pages |
020 - 21pp |
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Keywords |
inflation; cosmological parameters from CMBR; CMBR experiments |
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Abstract |
The value of the tensor-to-scalar ratio r in the region allowed by the latest Planck 2015 measurements can be associated to a large variety of inflationary models. We discuss here the potential of future Cosmic Microwave Background cosmological observations in disentangling among the possible theoretical scenarios allowed by our analyses of current Planck temperature and polarization data. Rather than focusing only on r, we focus as well on the running of the primordial power spectrum, alpha(s) and the running thereof, beta(s). If future cosmological measurements, as those from the COrE mission, confirm the current best-fit value for beta(s) greater than or similar to 10(-2) as the preferred one, it will be possible to rule-out the most favoured inflationary models. |
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Address |
[Escudero, Miguel; Ramirez, Hector; Boubekeur, Lotfi; Mena, Olga] Univ Valencia, CSIC, Inst Fis Corpuscular IFIC, Apartado Correos 22085, E-46071 Valencia, Spain, Email: miguel.escudero@ific.uv.es; |
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Corporate Author |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1475-7516 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000372467600021 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2590 |
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