| Records |
Author  |
Delhom, A.; Mariz, T.; Nascimento, J.R.; Olmo, G.J.; Petrov, A.Y.; Porfirio, P.J. |
| Title |
Spontaneous Lorentz symmetry breaking and one-loop effective action in the metric-affine bumblebee gravity |
Type |
Journal Article |
| Year |
2022 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
| Volume |
07 |
Issue |
7 |
Pages |
018 - 27pp |
| Keywords |
gravity; modified gravity; quantum field theory on curved space; Quantum fields in curved spacetimes |
| Abstract |
The metric-affine bumblebee model in the presence of fermionic matter minimally coupled to the connection is studied. We show that the model admits an Einstein frame representation in which the matter sector is described by a non-minimal Dirac action without any analogy in the literature. Such non-minimal terms involve unconventional couplings between the bumblebee and the fermion field. We then rewrite the quadratic fermion action in the Einstein frame in the basis of 16 Dirac matrices in order to identify the coefficients for Lorentz/CPT violation in all orders of the non-minimal coupling xi. The exact result for the fermionic determinant in the Einstein frame, including all orders in xi, is also provided. We demonstrate that the axial contributions are at least of second order in the perturbative expansion of xi. Furthermore, we compute the one-loop effective potential within the weak field approximation. |
| Address |
[Delhom, Adria] Univ Tartu, Inst Phys, Lab Theoret Phys, W Ostwaldi 1, EE-50411 Tartu, Estonia, Email: adria.delhom@gmail.com; |
| 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:000834157900011 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5314 |
| Permanent link to this record |
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| Author |
Delhom, A.; Nascimento, J.R.; Olmo, G.J.; Petrov, A.Y.; Porfirio, P.J. |
| Title |
Radiative corrections in metric-affine bumblebee model |
Type |
Journal Article |
| Year |
2022 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
| Volume |
826 |
Issue |
|
Pages |
136932 - 9pp |
| 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. |
| Address |
[Delhom, Adria; Olmo, Gonzalo J.] Univ Valencia, Ctr Mixto, Dept Fis Teor, CSIC, Valencia 46100, Spain, Email: adria.delhom@uv.es; |
| Corporate Author |
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Thesis |
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| Publisher |
Elsevier |
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 |
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 |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5229 |
| Permanent link to this record |
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| Author |
Delhom, A.; Nascimento, J.R.; Olmo, G.J.; Petrov, A.Y.; Porfirio, P.J. |
| Title |
Metric-affine bumblebee gravity: classical aspects |
Type |
Journal Article |
| Year |
2021 |
Publication |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
| Volume |
81 |
Issue |
4 |
Pages |
287 - 10pp |
| Keywords |
|
| 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 post-Minkowskian, weak-field limit and study the resulting effective theory. In this scenario, we couple scalar and spinorial matter to the effective metric, and then we explore the physical properties of the VEV of the bumblebee field, focusing mainly on the dispersion relations and the stability of the resulting effective theory. |
| Address |
[Delhom, Adria; Olmo, Gonzalo J.] Univ Valencia, Dept Fis Teor, Ctr Mixto Univ Valencia, CSIC, Valencia 46100, Spain, Email: adria.delhom@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 |
1434-6044 |
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:000636839400001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4779 |
| Permanent link to this record |
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| Author |
Heidari, N.; Hassanabadi, H.; Araujo Filho, A.A.; Kriz, J.; Zare, S.; Porfirio, P.J. |
| Title |
Gravitational signatures of a non-commutative stable black hole |
Type |
Journal Article |
| Year |
2024 |
Publication |
Physics of the Dark Universe |
Abbreviated Journal |
Phys. Dark Universe |
| Volume |
43 |
Issue |
|
Pages |
101382 - 13pp |
| Keywords |
Non-commutativity; Black hole; Shadows; Geodesics |
| Abstract |
This work investigates several key aspects of a non-commutative theory with mass deformation. We calculate thermodynamic properties of the system and compare our results with recent literature. We examine the quasinormal modes of massless scalar perturbations using two approaches: the WKB approximation and the Poschl-Teller fitting method. Our results indicate that stronger non-commutative parameters lead to slower damping oscillations of gravitational waves and higher partial absorption cross sections. Furthermore, we study the geodesics of massless and massive particles, highlighting that the non-commutative parameter (R) significantly impacts the paths of light and event horizons. Also, we calculate the shadows, which show that larger values of (R) correspond to larger shadow radii, and provide some constraints on (R) applying the observation of Sgr A* from the Event Horizon Telescope. Finally, we explore the deflection angle in this context. |
| Address |
[Heidari, N.; Hassanabadi, H.] Shahrood Univ Technol, Fac Phys, Shahrood, Iran, Email: heidari.n@gmail.com; |
| Corporate Author |
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Thesis |
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| Publisher |
Elsevier |
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 Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
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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:001126934800001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5857 |
| Permanent link to this record |
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| Author |
Nascimento, J.R.; Olmo, G.J.; Porfirio, P.J.; Petrov, A.Y.; Soares, A.R. |
| Title |
Nonlinear sigma-models in the Eddington-inspired Born-Infeld gravity |
Type |
Journal Article |
| Year |
2020 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
| Volume |
101 |
Issue |
6 |
Pages |
064043 - 11pp |
| Keywords |
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| Abstract |
In this paper we consider two different nonlinear sigma-models minimally coupled to Eddington-inspired Born-Infeld gravity. We show that the resultant geometries represent minimal modifications with respect to those found in GR, though with important physical consequences. In particular, wormhole structures always arise, though this does not guarantee by itself the geodesic completeness of those space-times. In one of the models, quadratic in the canonical kinetic term, we identify a subset of solutions which are regular everywhere and are geodesically complete. We discuss characteristic features of these solutions and their dependence on the relationship between mass and global charge. |
| Address |
[Nascimento, J. R.; Porfirio, P. J.; Petrov, A. Yu; Soares, A. R.] Univ Fed Paraiba, Dept Fis, Caixa Postal 5008, BR-58051970 Joao Pessoa, Paraiba, Brazil, Email: jroberto@fisica.ufpb.br; |
| Corporate Author |
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Thesis |
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| Publisher |
Amer Physical Soc |
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 |
2470-0010 |
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:000521099300008 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4344 |
| Permanent link to this record |
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| Author |
Nascimento, J.R.; Olmo, G.J.; Porfirio, P.J.; Petrov, A.Y.; Soares, A.R. |
| Title |
Global monopole in Palatini f(R) gravity |
Type |
Journal Article |
| Year |
2019 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
| Volume |
99 |
Issue |
6 |
Pages |
064053 - 11pp |
| Keywords |
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| Abstract |
We consider the space-time metric generated by a global monopole in an extension of general relativity (GR) of the form f(R) = R – lambda R-2. The theory is formulated in the metric-affine (or Palatini) formalism, and exact analytical solutions are obtained. For lambda < 0, one finds that the solution has the same characteristics as the Schwarzschild black hole with a monopole charge in Einstein's GR. For lambda > 0, instead, the metric is more closely related to the Reissner-Nordstrom metric with a monopole charge and, in addition, it possesses a wormhole-like structure that allows for the geodesic completeness of the spacetime. Our solution recovers the expected limits when lambda = 0 and also at the asymptotic far limit. The angular deflection of light in this space-time in the weak field regime is also calculated. |
| Address |
[Nascimento, J. R.; Petrov, A. Yu; Soares, A. R.] Univ Fed Paraiba, Dept Fis, Caixa Postal 5008, BR-58051970 Joao Pessoa, Paraiba, Brazil, Email: jroberto@fisica.ufpb.br; |
| Corporate Author |
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Thesis |
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| Publisher |
Amer Physical Soc |
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 |
2470-0010 |
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:000462920100010 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
3966 |
| Permanent link to this record |
