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Author |
Beltran Jimenez, J.; de Andres, D.; Delhom, A. |
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Title |
Anisotropic deformations in a class of projectively-invariant metric-affine theories of gravity |
Type |
Journal Article |
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Year |
2020 |
Publication |
Classical and Quantum Gravity |
Abbreviated Journal |
Class. Quantum Gravity |
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Volume |
37 |
Issue |
22 |
Pages |
225013 - 25pp |
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Keywords |
alternative theories of gravity; metric-affine gravity; anisotropic solutions |
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Abstract |
Among the general class of metric-affine theories of gravity, there is a special class conformed by those endowed with a projective symmetry. Perhaps the simplest manner to realise this symmetry is by constructing the action in terms of the symmetric part of the Ricci tensor. In these theories, the connection can be solved algebraically in terms of a metric that relates to the spacetime metric by means of the so-called deformation matrix that is given in terms of the matter fields. In most phenomenological applications, this deformation matrix is assumed to inherit the symmetries of the matter sector so that in the presence of an isotropic energy-momentum tensor, it respects isotropy. In this work we discuss this condition and, in particular, we show how the deformation matrix can be anisotropic even in the presence of isotropic sources due to the non-linear nature of the equations. Remarkably, we find that Eddington-inspired-Born-Infeld (EiBI) theories do not admit anisotropic deformations, but more general theories do. However, we find that the anisotropic branches of solutions are generally prone to a pathological physical behaviour. |
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Address |
[Jimenez, Jose Beltran] Univ Salamanca, Dept Fis Fundamental, E-37008 Salamanca, Spain, Email: jose.beltran@usal.es; |
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Iop Publishing Ltd |
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English |
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0264-9381 |
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Notes |
WOS:000580878200001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
4576 |
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Author |
Bejarano, C.; Delhom, A.; Jimenez-Cano, A.; Olmo, G.J.; Rubiera-Garcia, D. |
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Title |
Geometric inequivalence of metric and Palatini formulations of General Relativity |
Type |
Journal Article |
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Year |
2020 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
802 |
Issue |
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Pages |
135275 - 4pp |
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Keywords |
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Abstract |
Projective invariance is a symmetry of the Palatini version of General Relativity which is not present in the metric formulation. The fact that the Riemann tensor changes nontrivially under projective transformations implies that, unlike in the usual metric approach, in the Palatini formulation this tensor is subject to a gauge freedom, which allows some ambiguities even in its scalar contractions. In this sense, we show that for the Schwarzschild solution there exists a projective gauge in which the (affine) Kretschmann scalar, K (R beta μnu R alpha beta μnu)-R-alpha, can be set to vanish everywhere. This puts forward that the divergence of curvature scalars may, in some cases, be avoided by a gauge transformation of the connection. |
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Address |
[Bejarano, Cecilia] UBA, CONICET, IAFE, Casilla Correo 67,Sucursal 28, RA-1428 Buenos Aires, DF, Argentina, Email: cbejarano@iafe.uba.ar; |
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Elsevier |
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English |
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ISSN |
0370-2693 |
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Notes |
WOS:000515091400031 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4348 |
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Author |
Beltran Jimenez, J.; Delhom, A.; Olmo, G.J.; Orazi, E. |
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Title |
Born-Infeld gravity: Constraints from light-by-light scattering and an effective field theory perspective |
Type |
Journal Article |
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Year |
2021 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
820 |
Issue |
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Pages |
136479 - 6pp |
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Keywords |
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Abstract |
By using a novel technique that establishes a correspondence between general relativity and metric-affine theories based on the Ricci tensor, we are able to set stringent constraints on the free parameter of Born-Infeld gravity from the ones recently obtained for Born-Infeld electrodynamics by using light-by light scattering data from ATLAS. We also discuss how these gravity theories plus matter fit within an effective field theory framework. |
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Address |
[Beltran Jimenez, Jose] Univ Salamanca, Dept Fis Fundamental, E-37008 Salamanca, Spain, Email: jose.beltran@usal.es; |
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Elsevier |
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English |
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ISSN |
0370-2693 |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000701707400005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4978 |
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Author |
Delhom, A.; Nascimento, J.R.; Olmo, G.J.; Petrov, A.Y.; Porfirio, P.J. |
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Title |
Radiative corrections in metric-affine bumblebee model |
Type |
Journal Article |
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Year |
2022 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
826 |
Issue |
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Pages |
136932 - 9pp |
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Keywords |
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Abstract |
We consider the metric-affine formulation of bumblebee gravity, derive the field equations, and show that the connection can be written as Levi-Civita of a disformally related metric in which the bumblebee field determines the disformal part. As a consequence, the bumblebee field gets coupled to all the other matter fields present in the theory, potentially leading to nontrivial phenomenological effects. To explore this issue we compute the weak-field limit and study the resulting effective theory. In this scenario, we couple scalar and spinorial matter to the effective metric which, besides the zeroth-order Minkowskian contribution, also has the vector field contributions of the bumblebee, and show that it is renormalizable at one-loop level. From our analysis it also follows that the non-metricity of this theory is determined by the gradient of the bumblebee field, and that it can acquire a vacuum expectation value due to the contribution of the bumblebee field. |
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Address |
[Delhom, Adria; Olmo, Gonzalo J.] Univ Valencia, Ctr Mixto, Dept Fis Teor, CSIC, Valencia 46100, Spain, Email: adria.delhom@uv.es; |
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Elsevier |
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English |
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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 |
0370-2693 |
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:000792884500005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5229 |
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Author |
Delhom, A.; Olmo, G.J.; Orazi, E. |
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Title |
Ricci-Based Gravity theories and their impact on Maxwell and nonlinear electromagnetic models |
Type |
Journal Article |
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Year |
2019 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
11 |
Issue |
11 |
Pages |
149 - 24pp |
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Keywords |
Classical Theories of Gravity; Beyond Standard Model |
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Abstract |
We extend the correspondence between metric-affine Ricci-Based Gravity the- ories and General Relativity (GR) to the case in which the matter sector is represented by linear and nonlinear electromagnetic fields. This complements previous studies focused on fluids and scalar fields. We establish the general algorithm that relates the matter fields in the GR and RBG frames and consider some applications. In particular, we find that the so-called Eddington-inspired Born-Infeld gravity theory coupled to Maxwell electromag- netism is in direct correspondence with GR coupled to Born-Infeld electromagnetism. We comment on the potential phenomenological implications of this relation. |
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Address |
[Delhom, Adria; Olmo, Gonzalo J.] Univ Valencia, Dept Fis Teor, E-46100 Valencia, Spain, Email: adria.delhom@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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Language |
English |
Summary Language |
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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 |
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:000513489000001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4281 |
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