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Author |
Cervantes-Cota, J.L.; de Putter, R.; Linder, E.V. |
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Title |
Induced gravity and the attractor dynamics of dark energy/dark matter |
Type |
Journal Article |
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Year |
2010 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
12 |
Issue |
12 |
Pages |
019 - 20pp |
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Keywords |
modified gravity; dark energy theory |
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Abstract |
Attractor solutions that give dynamical reasons for dark energy to act like the cosmological constant, or behavior close to it, are interesting possibilities to explain cosmic acceleration. Coupling the scalar field to matter or to gravity enlarges the dynamical behavior; we consider both couplings together, which can ameliorate some problems for each individually. Such theories have also been proposed in a Higgs-like fashion to induce gravity and unify dark energy and dark matter origins. We explore restrictions on such theories due to their dynamical behavior compared to observations of the cosmic expansion. Quartic potentials in particular have viable stability properties and asymptotically approach general relativity. |
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Address |
[Cervantes-Cota, Jorge L.] Inst Nacl Invest Nucl, Dept Fis, Mexico City 11801, DF, Mexico, Email: jorge.cervantes@inin.gob.mx |
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Publisher |
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 |
ISI:000286930700019 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
533 |
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Author |
Girones, Z.; Marchetti, A.; Mena, O.; Pena-Garay, C.; Rius, N. |
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Title |
Cosmological data analysis of f(R) gravity models |
Type |
Journal Article |
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Year |
2010 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
11 |
Issue |
11 |
Pages |
004 - 18pp |
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Keywords |
modified gravity; cosmological parameters from LSS |
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Abstract |
A class of well-behaved modified gravity models with long enough matter domination epoch and a late-time accelerated expansion is confronted with SNIa, CMB, SDSS, BAO and H(z) galaxy ages data, as well as current measurements of the linear growth of structure. We show that the combination of geometrical probes and growth data exploited here allows to rule out f(R) gravity models, in particular, the logarithmic of curvature model. We also apply solar system tests to the models in agreement with the cosmological data. We find that the exponential of the inverse of the curvature model satisfies all the observational tests considered and we derive the allowed range of parameters. Current data still allows for small deviations of Einstein gravity. Future, high precision growth data, in combination with expansion history data, will be able to distinguish tiny modifications of standard gravity from the Lambda CDM model. |
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Address |
[Girones, Z.; Marchetti, A.; Mena, O.; Pena-Garay, C.; Rius, N.] Univ Valencia, CSIC, IFIC, Dept Fis Teor, Valencia 46071, Spain, Email: girones@ific.uv.es |
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Publisher |
Iop Publishing Ltd |
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Language |
English |
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Series Editor |
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Series Volume |
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ISSN |
1475-7516 |
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Expedition |
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Conference |
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Notes |
ISI:000284825100004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ elepoucu @ |
Serial |
315 |
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Author |
Galli, P.; Goldstein, K.; Katmadas, S.; Perz, J. |
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Title |
First-order flows and stabilisation equations for non-BPS extremal black holes |
Type |
Journal Article |
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Year |
2011 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
06 |
Issue |
6 |
Pages |
070 - 28pp |
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Keywords |
Black Holes in String Theory; Supergravity Models |
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Abstract |
We derive a generalised form of flow equations for extremal static and rotating non-BPS black holes in four-dimensional ungauged N = 2 supergravity coupled to vector multiplets. For particular charge vectors, we give stabilisation equations for the scalars, analogous to the BPS case, describing full known solutions. Based on this, we propose a generic ansatz for the stabilisation equations, which surprisingly includes ratios of harmonic functions. |
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Address |
[Galli, P] Univ Valencia, Dept Fis Teor, E-46100 Burjassot, Valencia, Spain, Email: Pietro.Galli@ific.uv.es |
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Thesis |
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Publisher |
Springer |
Place of Publication |
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Language |
English |
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Series Volume |
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Edition |
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ISSN |
1126-6708 |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000293136500070 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
746 |
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Author |
Olmo, G.J. |
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Title |
Palatini actions and quantum gravity phenomenology |
Type |
Journal Article |
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Year |
2011 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
10 |
Issue |
10 |
Pages |
018 - 15pp |
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Keywords |
quantum gravity phenomenology; cosmic singularity |
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Abstract |
We show that an invariant an universal length scale can be consistently introduced in a generally covariant theory through the gravitational sector using the Palatini approach. The resulting theory is able to capture different aspects of quantum gravity phenomenology in a single framework. In particular, it is found that in this theory field excitations propagating with different energy-densities perceive different background metrics, which is a fundamental characteristic of the DSR and Rainbow Gravity approaches. We illustrate these properties with a particular gravitational model and explicitly show how the soccer ball problem is avoided in this framework. The isotropic and anisotropic cosmologies of this model also avoid the big bang singularity by means of a big bounce. |
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Address |
[Olmo, GJ] Univ Valencia, Dept Fis Teor, E-46100 Valencia, Spain, Email: gonzalo.olmo@csic.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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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:000296767600018 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ elepoucu @ |
Serial |
816 |
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Author |
Olmo, G.J. |
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Title |
Palatini approach to modified gravity: f(R) theories and beyond |
Type |
Journal Article |
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Year |
2011 |
Publication |
International Journal of Modern Physics D |
Abbreviated Journal |
Int. J. Mod. Phys. D |
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Volume |
20 |
Issue |
4 |
Pages |
413-462 |
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Keywords |
Palatini formalism; modified gravity; cosmic speed-up; dark energy; dark matter; MOND; quantum gravity phenomenology; Hamiltonian formulation; stellar structure; Cauchy problem; solar system tests |
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Abstract |
We review the recent literature on modified theories of gravity in the Palatini approach. After discussing the motivations that lead to consider alternatives to Einstein's theory and to treat the metric and the connection as independent objects, we review several topics that have been recently studied within this framework. In particular, we provide an in-depth analysis of the cosmic speed-up problem, laboratory and solar system tests, the structure of stellar objects, the Cauchy problem, and bouncing cosmologies. We also discuss the importance of going beyond the f(R) models to capture other phenomenological aspects related with dark matter/energy and quantum gravity. |
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Address |
[Olmo, Gonzalo J.] Univ Valencia CSIC, Dept Fis Teor, Valencia, Spain, Email: gonzalo.olmo@uv.es |
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Corporate Author |
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Thesis |
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Publisher |
World Scientific Publ Co Pte 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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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 |
0218-2718 |
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:000290228200001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
961 |
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Author |
Borja, E.F.; Garay, I.; Vidotto, F. |
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Title |
Learning about Quantum Gravity with a Couple of Nodes |
Type |
Journal Article |
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Year |
2012 |
Publication |
Symmetry Integrability and Geometry-Methods and Applications |
Abbreviated Journal |
Symmetry Integr. Geom. |
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Volume |
8 |
Issue |
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Pages |
015 - 44pp |
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Keywords |
discrete gravity; canonical quantization; spinors; spinfoam; quantum cosmology |
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Abstract |
Loop Quantum Gravity provides a natural truncation of the infinite degrees of freedom of gravity, obtained by studying the theory on a given finite graph. We review this procedure and we present the construction of the canonical theory on a simple graph, formed by only two nodes. We review the U(N) framework, which provides a powerful tool for the canonical study of this model, and a formulation of the system based on spinors. We consider also the covariant theory, which permits to derive the model from a more complex formulation, paying special attention to the cosmological interpretation of the theory. |
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Address |
[Borja, Enrique F.; Garay, Inaki] Univ Erlangen Nurnberg, Inst Theoret Phys 3, D-91058 Erlangen, Germany, Email: efborja@theorie3.physik.uni-erlangen.de; |
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Publisher |
Natl Acad Sci Ukraine, Inst Math |
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Language |
English |
Summary Language |
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Original Title |
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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 |
1815-0659 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000303831400001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1018 |
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Author |
Galli, P.; Ortin, T.; Perz, J.; Shahbazi, C.S. |
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Title |
From supersymmetric to non-supersymmetric black holes |
Type |
Journal Article |
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Year |
2012 |
Publication |
Fortschritte der Physik-Progress of Physics |
Abbreviated Journal |
Fortschritte Phys.-Prog. Phys. |
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Volume |
60 |
Issue |
9-10 |
Pages |
1026-1029 |
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Keywords |
Black holes; supergravity |
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Abstract |
Methods similar to those used for obtaining supersymmetric black hole solutions can be employed to find also non-supersymmetric solutions. We briefly review some of them, with the emphasis on the non-extremal deformation ansatz of [1]. |
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Address |
[Ortin, Tomas; Perz, Jan; Shahbazi, C. S.] Inst Fis Teor UAM CSIC, Madrid 28049, Spain, Email: Pietro.Galli@ific.uv.es; |
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Thesis |
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Publisher |
Wiley-V C H Verlag Gmbh |
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Language |
English |
Summary Language |
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Original Title |
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Series Issue |
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Edition |
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ISSN |
0015-8208 |
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:000308301500012 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
1151 |
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| Permanent link to this record |
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Author |
Olmo, G.J.; Rubiera-Garcia, D. |
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Title |
Nonsingular Charged Black Holes A La Palatini |
Type |
Journal Article |
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Year |
2012 |
Publication |
International Journal of Modern Physics D |
Abbreviated Journal |
Int. J. Mod. Phys. D |
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Volume |
21 |
Issue |
8 |
Pages |
1250067 - 6pp |
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Keywords |
Extended theories of gravity; Palatini formalism; Planck scale |
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Abstract |
We argue that the quantum nature of matter and gravity should lead to a discretization of the allowed states of the matter confined in the interior of black holes. To support and illustrate this idea, we consider a quadratic extension of general relativity (GR) formulated a la Palatini and show that nonrotating, electrically charged black holes develop a compact core at the Planck density which is nonsingular if the mass spectrum satisfies a certain discreteness condition. We also find that the area of the core is proportional to the number of charges times the Planck area. |
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Address |
[Olmo, Gonzalo J.] Univ Valencia, CSIC, Dept Fis Teor, Fac Fis, E-46100 Valencia, Spain |
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Corporate Author |
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Thesis |
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Publisher |
World Scientific Publ Co Pte 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 |
0218-2718 |
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:000308497500002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
1154 |
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Author |
Creminelli, P.; Norena, J.; Pena, M.; Simonovic, M. |
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Title |
Khronon inflation |
Type |
Journal Article |
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Year |
2012 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
11 |
Issue |
11 |
Pages |
032 - 16pp |
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Keywords |
inflation; modified gravity; non-gaussianity |
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Abstract |
We study the possibility that the approximate time shift symmetry during inflation is promoted to the full invariance under time reparametrization t -> (t) over tilde (t), or equivalently under field redefinition of the inflaton phi -> (phi) over tilde(phi). The symmetry allows only two operators at leading order in derivatives, so that all n-point functions of scalar perturbations are fixed in terms of the power spectrum normalization and the speed of sound. During inflation the decaying mode only decays as 1/a and this opens up the possibility to violate some of the consistency relations in the squeezed limit, although this violation is suppressed by the (small) breaking of the field reparametrization symmetry. In particular one can get terms in the 3-point function that are only suppressed by 1/k(L) in the squeezed limit k(L) -> 0 compared to the local shape. |
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Address |
[Creminelli, Paolo] Abdus Salam Int Ctr Theoret Phys, I-34151 Trieste, Italy, Email: creminel@ictp.it; |
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Thesis |
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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:000312263500015 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1274 |
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| Permanent link to this record |
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Author |
Galli, P.; Goldstein, K.; Perz, J. |
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Title |
On anharmonic stabilisation equations for black holes |
Type |
Journal Article |
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Year |
2013 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
03 |
Issue |
3 |
Pages |
036 - 7pp |
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Keywords |
Black Holes in String Theory; Supergravity Models |
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Abstract |
We investigate the stabilisation equations for sufficiently general, yet regular, extremal (supersymmetric and non-supersymmetric) and non-extremal black holes in four-dimensional N = 2 supergravity using both the H-FGK approach and a generalisation of Denef's formalism. By an explicit calculation we demonstrate that the equations necessarily contain an anharmonic part, even in the static, spherically symmetric and asymptotically flat case. |
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Address |
Univ Valencia, Dept Fis Teor, E-46100 Burjassot, Valencia, Spain, Email: Pietro.Galli@ific.uv.es; |
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Corporate Author |
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Thesis |
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Publisher |
Springer |
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 |
1029-8479 |
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:000317521200036 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1417 |
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