| Records |
| Author |
Beltran Jimenez, J.; Heisenberg, L.; Olmo, G.J.; Rubiera-Garcia, D. |
| Title |
On gravitational waves in Born-Infeld inspired non-singular cosmologies |
Type |
Journal Article |
| Year |
2017 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
| Volume |
10 |
Issue |
10 |
Pages |
029 - 23pp |
| Keywords |
alternatives to inflation; modified gravity; physics of the early universe; primordial gravitational waves (theory) |
| Abstract |
We study the evolution of gravitational waves for non-singular cosmological solutions within the framework of Born-Infeld inspired gravity theories, with special emphasis on the Eddington-inspired Born-Infeld theory. We review the existence of two types of non-singular cosmologies, namely bouncing and asymptotically Minkowski solutions, from a perspective that makes their features more apparent. We study in detail the propagation of gravitational waves near these non-singular solutions and carefully discuss the origin and severity of the instabilities and strong coupling problems that appear. We also investigate the role of the adiabatic sound speed of the matter sector in the regularisation of the gravitational waves evolution. We extend our analysis to more general Born-Infeld inspired theories where analogous solutions are found. As a general conclusion, we obtain that the bouncing solutions are generally more prone to instabilities, while the asymptotically Minkowski solutions can be rendered stable, making them appealing models for the early universe. |
| Address |
[Beltran Jimenez, Jose] Univ Toulon & Var, Aix Marseille Univ, CNRS, CPT, Marseille, France, Email: jose.beltran@uam.es; |
| Corporate Author |
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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:000413332400002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
3337 |
| Permanent link to this record |
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| Author |
Olmo, G.J.; Rubiera-Garcia, D.; Sanchez-Puente, A. |
| Title |
Accelerated observers and the notion of singular spacetime |
Type |
Journal Article |
| Year |
2018 |
Publication |
Classical and Quantum Gravity |
Abbreviated Journal |
Class. Quantum Gravity |
| Volume |
35 |
Issue |
5 |
Pages |
055010 - 18pp |
| Keywords |
general relativity; geodesic behaviour; black holes; spacetime singularities; modified theories of gravity |
| Abstract |
Geodesic completeness is typically regarded as a basic criterion to determine whether a given spacetime is regular or singular. However, the principle of general covariance does not privilege any family of observers over the others and, therefore, observers with arbitrary motions should be able to provide a complete physical description of the world. This suggests that in a regular spacetime, all physically acceptable observers should have complete paths. In this work we explore this idea by studying the motion of accelerated observers in spherically symmetric spacetimes and illustrate it by considering two geodesically complete black hole spacetimes recently described in the literature. We show that for bound and locally unbound accelerations, the paths of accelerated test particles are complete, providing further support to the regularity of such spacetimes. |
| Address |
[Olmo, Gonzalo J.; Sanchez-Puente, Antonio] Univ Valencia, Dept Fis Teor, CSIC, Ctr Mixto, E-46100 Valencia, Spain, Email: gonzalo.olmo@uv.es; |
| Corporate Author |
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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 |
0264-9381 |
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:000424042100001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
3473 |
| Permanent link to this record |
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| Author |
Galli, P.; Goldstein, K.; Katmadas, S.; Perz, J. |
| Title |
First-order flows and stabilisation equations for non-BPS extremal black holes |
Type |
Journal Article |
| Year |
2011 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
06 |
Issue |
6 |
Pages |
070 - 28pp |
| Keywords |
Black Holes in String Theory; Supergravity Models |
| 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. |
| Address |
[Galli, P] Univ Valencia, Dept Fis Teor, E-46100 Burjassot, Valencia, Spain, Email: Pietro.Galli@ific.uv.es |
| 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 |
1126-6708 |
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:000293136500070 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ elepoucu @ |
Serial |
746 |
| Permanent link to this record |
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| Author |
Galli, P.; Meessen, P.; Ortin, T. |
| Title |
The Freudenthal gauge symmetry of the black holes of N=2, d=4 supergravity |
Type |
Journal Article |
| Year |
2013 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
05 |
Issue |
5 |
Pages |
011 - 15pp |
| Keywords |
Black Holes; String Duality; Gauge Symmetry; Supergravity Models |
| Abstract |
We show that the representation of black-hole solutions in terms of the variables H-M which are harmonic functions in the supersymmetric case is non-unique due to the existence of a local symmetry in the effective action. This symmetry is a continuous (and local) generalization of the discrete Freudenthal transformations initially introduced for the black-hole charges and can be used to rewrite the physical fields of a solution in terms of entirely different-looking functions. |
| Address |
[Galli, Pietro] Univ Valencia, Dept Fis Teor, E-46100 Burjassot, Valencia, Spain, Email: Pietro.Galli@ific.uv.es; |
| 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:000321374400011 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ pastor @ |
Serial |
1555 |
| Permanent link to this record |
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| Author |
Olmo, G.J.; Rubiera-Garcia, D. |
| Title |
Semiclassical geons at particle accelerators |
Type |
Journal Article |
| Year |
2014 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
| Volume |
02 |
Issue |
2 |
Pages |
010 - 25pp |
| Keywords |
modified gravity; Wormholes; quantum black holes |
| Abstract |
We point out that in certain four-dimensional extensions of general relativity constructed within the Palatini formalism stable self-gravitating objects with a discrete mass and charge spectrum may exist. The incorporation of nonlinearities in the electromagnetic field may effectively reduce their mass spectrum by many orders of magnitude. As a consequence, these objects could be within (or near) the reach of current particle accelerators. We provide an exactly solvable model to support this idea. |
| Address |
[Omla, Gonzalo J.] Univ Valencia, CSIC, Dept Fis Teor, E-46100 Valencia, Spain, Email: gonzalo.olmo@csic.es; |
| Corporate Author |
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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:000332711400010 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
1733 |
| Permanent link to this record |
