Records |
Author |
Andrade, I.; Bazeia, D.; Marques, M.A.; Menezes, R.; Olmo, G.J. |
Title |
Analytical solutions for Maxwell-scalar system on radially symmetric spacetimes |
Type |
Journal Article |
Year  |
2025 |
Publication |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
Volume |
85 |
Issue |
1 |
Pages |
27 - 15pp |
Keywords |
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Abstract |
We investigate Maxwell-scalar models on radially symmetric spacetimes in which the gauge and scalar fields are coupled via the electric permittivity. We find the conditions that allow for the presence of minimum energy configurations. In this formalism, the charge density must be written exclusively in terms of the components of the metric tensor and the scalar field is governed by first-order equations. We also find a manner to map the aforementioned equation into the corresponding one associated to kinks in (1, 1) spacetime dimensions, so we get analytical solutions for three specific spacetimes. We then calculate the energy density and show that the energy is finite. The stability of the solutions against contractions and dilations, following Derrick's argument, and around small fluctuations in the fields is also investigated. In this direction, we show that the solutions obeying the first-order framework are stable. |
Address |
[Andrade, I.; Bazeia, D.] Univ Fed Paraiba, Dept Fis, BR-58051970 Joao Pessoa, Paraiba, Brazil, Email: andradesigor0@gmail.com; |
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Thesis |
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Publisher |
Springer |
Place of Publication |
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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 |
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:001399512300003 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
6445 |
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Author |
Maso-Ferrando, A.; Sanchis-Gual, N.; Font, J.A.; Olmo, G.J. |
Title |
Numerical evolutions of boson stars in Palatini f(R) gravity |
Type |
Journal Article |
Year  |
2024 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
Volume |
109 |
Issue |
4 |
Pages |
044042 - 14pp |
Keywords |
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Abstract |
We investigate the time evolution of spherically symmetric boson stars in Palatini f(R) gravity through numerical relativity computations. Employing a novel approach that establishes a correspondence between modified gravity with scalar matter and general relativity with modified scalar matter, we are able to use the techniques of numerical relativity to simulate these systems. Specifically, we focus on the quadratic theory f(R) = R + xi R2 and compare the obtained solutions with those in general relativity, exploring both positive and negative values of the coupling parameter xi. Our findings reveal that boson stars in Palatini f(R) gravity exhibit both stable and unstable evolutions. The latter give rise to three distinct scenarios: migration toward a stable configuration, complete dispersion, and gravitational collapse leading to the formation of a baby universe structure. |
Address |
[Maso-Ferrando, Andreu; Olmo, Gonzalo J.] Ctr Mixto Univ Valencia, Univ Valencia, Dept Fis Teor, CSIC, Burjassot 46100, Valencia, Spain, Email: andreu.maso@uv.es; |
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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:001186268100006 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
6035 |
Permanent link to this record |
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Author |
Nascimento, J.R.; Olmo, G.J.; Petrov, A.Y.; Porfirio, P.J. |
Title |
On metric-affine bumblebee model coupled to scalar matter |
Type |
Journal Article |
Year  |
2024 |
Publication |
Nuclear Physics B |
Abbreviated Journal |
Nucl. Phys. B |
Volume |
1004 |
Issue |
|
Pages |
116577 - 10pp |
Keywords |
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Abstract |
We consider the coupling of the metric-affine bumblebee gravity model to scalar matter and calculate the lower -order contributions to two -point functions of bumblebee and scalar fields in the weak gravity approximation. We also obtain the one -loop effective potentials for both scalar and vector fields. |
Address |
[Nascimento, J. R.; Petrov, A. Yu.; Porfirio, P. J.] Univ Fed Paraiba, Dept Fis, Caixa Postal 5008, BR-58051970 Joao Pessoa, PB, Brazil, Email: jroberto@fisica.ufpb.br; |
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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 |
0550-3213 |
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:001248177100001 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
6157 |
Permanent link to this record |
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Author |
Maluf, R.V.; Mora-Perez, G.; Olmo, G.J.; Rubiera-Garcia, D. |
Title |
Nonsingular, Lump-like, Scalar Compact Objects in (2+1)-Dimensional Einstein Gravity |
Type |
Journal Article |
Year  |
2024 |
Publication |
Universe |
Abbreviated Journal |
Universe |
Volume |
10 |
Issue |
6 |
Pages |
258 - 13pp |
Keywords |
Einstein gravity; compact objects; nonlinear scalar field |
Abstract |
We study the space-time geometry generated by coupling a free scalar field with a noncanonical kinetic term to general relativity in (2+1) dimensions. After identifying a family of scalar Lagrangians that yield exact analytical solutions in static and circularly symmetric scenarios, we classify the various types of solutions and focus on a branch that yields asymptotically flat geometries. We show that the solutions within such a branch can be divided in two types, namely naked singularities and nonsingular objects without a center. In the latter, the energy density is localized around a maximum and vanishes only at infinity and at an inner boundary. This boundary has vanishing curvatures and cannot be reached by any time-like or null geodesic in finite affine time. This allows us to consistently interpret such solutions as nonsingular, lump-like, static compact scalar objects whose eventual extension to the (3+1)-dimensional context could provide structures of astrophysical interest. |
Address |
[Maluf, Roberto V.; Olmo, Gonzalo J.] Univ Fed Ceara UFC, Dept Fis, Campus Pici, BR-60455760 Fortaleza, Ceara, Brazil, Email: r.v.maluf@fisica.ufc.br; |
Corporate Author |
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Thesis |
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Publisher |
Mdpi |
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 |
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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:001256495600001 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
6169 |
Permanent link to this record |
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Author |
Magalhaes, R.B.; Ribeiro, G.P.; Lima, H.C.D.J.; Olmo, G.J.; Crispino, L.C.B. |
Title |
Singular space-times with bounded algebraic curvature scalars |
Type |
Journal Article |
Year  |
2024 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
Volume |
05 |
Issue |
5 |
Pages |
114 - 34pp |
Keywords |
gravity; modified gravity; Wormholes |
Abstract |
We show that the absence of unbounded algebraic curvature invariants constructed from polynomials of the Riemann tensor cannot guarantee the absence of strong singularities. As a consequence, it is not sufficient to rely solely on the analysis of such scalars to assess the regularity of a given space-time. This conclusion follows from the analysis of incomplete geodesics within the internal region of asymmetric wormholes supported by scalar matter which arise in two distinct metric-affine gravity theories. These wormholes have bounded algebraic curvature scalars everywhere, which highlights that their finiteness does not prevent the emergence of pathologies (singularities) in the geodesic structure of space-time. By analyzing the tidal forces in the internal wormhole region, we find that the angular components are unbounded along incomplete radial time-like geodesics. The strength of the singularity is determined by the evolution of Jacobi fields along such geodesics, finding that it is of strong type, as volume elements are torn apart as the singularity is approached. Lastly, and for completeness, we consider the wormhole of the quadratic Palatini theory and present an analysis of the tidal forces in the entire space-time. |
Address |
[Magalhaes, Renan B.; Ribeiro, Gabriel P.; Lima Jr, Haroldo C. D.; Crispino, Luis C. B.] Univ Fed Para, Programa Posgrad Fis, BR-66075110 Belem, Para, Brazil, Email: renan.magalhaes@icen.ufpa.br; |
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:001265908300012 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
6200 |
Permanent link to this record |
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Author |
Castillo-Felisola, O.; Grez, B.; Olmo, G.J.; Orellana, O.; Perdiguero Garate, J. |
Title |
Cosmological solutions in polynomial affine gravity with torsion |
Type |
Journal Article |
Year  |
2024 |
Publication |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
Volume |
84 |
Issue |
9 |
Pages |
900 - 12pp |
Keywords |
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Abstract |
The Polynomial Affine Gravity is an alternative gravitational model, where the interactions are mediated solely by the affine connection, instead of the metric tensor. In this paper, we explore the space of solutions to the field equations when the torsion fields are turned on, in a homogeneous and isotropic (cosmological) scenario. We explore various metric structures that emerge in the space of solutions. |
Address |
[Castillo-Felisola, Oscar; Grez, Bastian] Univ Tecn Federico Santa Maria, Dept Fis, Casilla 110-V, Valparaiso, Chile |
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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:001307826500001 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
6251 |
Permanent link to this record |
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Author |
Magalhaes, R.B.; Maso-Ferrando, A.S.; Bombacigno, F.; Olmo, G.J.; Crispino, L.C.B. |
Title |
Echoes from bounded universes |
Type |
Journal Article |
Year  |
2024 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
Volume |
110 |
Issue |
4 |
Pages |
044058 - 21pp |
Keywords |
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Abstract |
We construct a general class of modified Ellis-Bronnikov wormholes, where one asymptotic Minkowski region is replaced by a bounded 2-sphere core, characterized by an asymptotic finite areal radius. We pursue an in-depth analysis of the resulting geometry, outlining that geodesic completeness is also guaranteed when the area function asymptotically shrinks to zero. Moreover, we perform an analysis of the circular orbits present in our model and conclude that stable circular orbits are allowed in the bounded region. As a consequence, a stable light ring may exist in the inner region and trapped orbits may appear within this bounded region. Such internal structure suggests that the bounded region can trap perturbations. Then, we study the evolution of scalar perturbations, bringing out how these geometric configurations can in principle affect the time-domain profiles of quasinormal modes, pointing out the distinctive features with respect to other black hole or wormhole geometries. |
Address |
[Magalhaes, Renan B.; Crispino, Luis C. B.] Univ Fed Para, Programa Posgrad Fis, BR-66075110 Belem, PA, Brazil, Email: renan.magalhaes@icen.ufpa.br; |
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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:001306781100003 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
6260 |
Permanent link to this record |
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Author |
Batool, A.; Malik Sultan, A.; Olmo, G.J.; Rubiera-Garcia, D. |
Title |
Stellar structure in f(R,T) gravity: Some exact solutions |
Type |
Journal Article |
Year  |
2024 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
Volume |
110 |
Issue |
6 |
Pages |
064059 - 6pp |
Keywords |
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Abstract |
We find some exact solutions for constant-density and quark matter equations of state in stellar structure models framed within the f(R, T) = R + lambda(KT)-T-2 theory of gravity, where R is the curvature scalar, T the trace of the stress-energy tensor, and lambda some constant. These solutions correspond to specific values of the constant lambda and represent different compactness states of the corresponding stars, though only those made of quark matter can be regarded as physical. The latter modify the compactness (Buchdahl) limit of neutron stars upward for lambda > 0 until saturating the one of black holes. Our results show that it is possible to find useful insights on stellar structure in this class of theories, a fact that could be used for obtaining constraints on limiting masses such as the minimum hydrogen burning mass. |
Address |
[Batool, Aliya; Sultan, Abdul Malik] Univ Okara, Dept Math, Okara 56300, Pakistan, Email: syedaaliyabatool123@gmail.com; |
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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:001318370200018 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
6265 |
Permanent link to this record |
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Author |
Mora-Perez, G.; Olmo, G.J.; Rubiera-Garcia, D.; Saez-Chillon Gomez, D. |
Title |
Boundary terms and on-shell action in Ricci-based gravity theories: The Hamiltonian formulation |
Type |
Journal Article |
Year  |
2024 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
Volume |
110 |
Issue |
8 |
Pages |
084051 - 11pp |
Keywords |
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Abstract |
Considering the so-called Ricci-based gravity theories, a family of extensions of general relativity whose action is given by a nonlinear function of contractions and products of the (symmetric part of the) Ricci tensor of an independent connection, the Hamiltonian formulation of the theory is obtained. To do so, the independent connection is decomposed in two parts, one compatible with a metric tensor and the other one given by a 3-rank tensor. Subsequently, the Riemann tensor is expressed in terms of its projected components onto a hypersurface, allowing one to construct the 3 & thorn; 1 decomposition of the theory and the corresponding Gauss-Codazzi relations, where the boundary terms naturally arise in the gravitational action. Finally, the Arnowitt-Deser-Misner (ADM) decomposition is followed in order to construct the corresponding Hamiltonian and the ADM energy for any Ricci-based gravity theory. The formalism is applied to the simple case of Schwarzschild spacetime. |
Address |
[Mora-Perez, Gerardo; Olmo, Gonzalo J.] Univ Valencia, Dept Fis Teor, Valencia 46100, Spain, Email: gonzalo.olmo@uv.es; |
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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:001343522900002 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
6326 |
Permanent link to this record |
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Author |
Almeida, C.A.S.; Lima, F.C.E.; Mishra, S.S.; Olmo, G.J.; Sahoo, P.K. |
Title |
Thick brane in mimetic-like gravity |
Type |
Journal Article |
Year  |
2024 |
Publication |
Nuclear Physics B |
Abbreviated Journal |
Nucl. Phys. B |
Volume |
1009 |
Issue |
|
Pages |
116747 - 9pp |
Keywords |
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Abstract |
We analyze a five-dimensional braneworld governed by a mimetic-like gravity, a plausible candidate for explaining dark matter. Within this scenario, we examine Friedmann-Lemaitre-Robertson-Walker (FLRW) branes and find that constant curvature and Minkowskian solutions are possible. We then show that the mimetic model leads to kink-like and lump-like thick brane solutions without the need for spontaneous symmetry breaking. Its stability against small perturbations is also verified. |
Address |
[Almeida, C. A. S.; Lima, F. C. E.; Olmo, Gonzalo J.] Univ Fed Ceara UFC, Dept Fis, Campus Pici, BR-60455760 Fortaleza, CE, Brazil, Email: carlos@fisica.ufc.br; |
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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 |
0550-3213 |
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:001362181800001 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
6344 |
Permanent link to this record |