| Records |
| Author |
Maso-Ferrando, A.; Sanchis-Gual, N.; Font, J.A.; Olmo, G.J. |
| Title |
Birth of baby universes from gravitational collapse in a modified-gravity scenario |
Type |
Journal Article |
| Year |
2023 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
| Volume |
06 |
Issue |
6 |
Pages |
028 - 19pp |
| Keywords |
modified gravity; Wormholes |
| Abstract |
We consider equilibrium models of spherical boson stars in Palatini f (R) = R + CR2 gravity and study their collapse when perturbed. The Einstein-Klein-Gordon system is solved using a recently established correspondence in an Einstein frame representation. We find that, in that frame, the endpoint is a nonrotating black hole surrounded by a quasi -stationary cloud of scalar field. However, the dynamics in the f (R) frame is dramatically different. The innermost region of the collapsing object exhibits the formation of a finite -size, exponentially-expanding baby universe connected with the outer (parent) universe via a minimal area surface (a throat or umbilical cord). Our simulations indicate that this surface is at all times hidden inside a horizon, causally disconnecting the baby universe from observers above the horizon. The implications of our findings in other areas of gravitational physics are also discussed. |
| Address |
[Maso-Ferrando, Andreu; Olmo, Gonzalo J.] Univ Valencia, Ctr Mixto, CSIC, Dept Fis Teor, Valencia 46100, Spain, Email: andreu.maso@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 |
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:001025474200010 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5577 |
| Permanent link to this record |
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| Author |
Santos, A.C.L.; Muniz, C.R.; Maluf, R.V. |
| Title |
Yang-Mills Casimir wormholes in D=2+1 |
Type |
Journal Article |
| Year |
2023 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
| Volume |
09 |
Issue |
9 |
Pages |
022 - 24pp |
| Keywords |
Wormholes; Exact solutions; black holes and black hole thermodynamics in GR and beyond; gravity |
| Abstract |
This work presents new three-dimensional traversable wormhole solutions sourced by the Casimir density and pressures related to the quantum vacuum fluctuations in Yang-Mills (Y-M) theory. We begin by analyzing the noninteracting Y-M Casimir wormholes, initially considering an arbitrary state parameter omega and determine a simple constant wormhole shape function. Next, we introduce a new methodology for deforming the state parameter to find well-behaved redshift functions. The wormhole can be interpreted as a legitimate Casimir wormhole with an expected average state parameter of omega = 2. Then, we investigate the wormhole curvature properties, energy conditions, and stability. Furthermore, we discover a novel family of traversable wormhole solutions sourced by the quantum vacuum fluctuations of interacting Yang-Mills fields with a more complex shape function. Deforming the effective state parameter similarly, we obtain well-behaved redshift functions and traversable wormhole solutions. Finally, we examine the energy conditions and stability of solutions in the interacting scenario and compare to the noninteracting case. |
| Address |
[Santos, Alana C. L.; Maluf, Roberto V.] Univ Fed Ceara UFC, Departamento Fis, Campus Pici,6030, BR-60455760 Fortaleza, Ceara, Brazil, Email: alanasantos@fisica.ufc.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:001196198800004 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
6031 |
| Permanent link to this record |
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| Author |
Guendelman, E.I.; Olmo, G.J.; Rubiera-Garcia, D.; Vasihoun, M. |
| Title |
Nonsingular electrovacuum solutions with dynamically generated cosmological constant |
Type |
Journal Article |
| Year |
2013 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
| Volume |
726 |
Issue |
4-5 |
Pages |
870-875 |
| Keywords |
Modified gravity; Palatini formalism; Nonlinear electrodynamics; Dynamical cosmological constant; Nonsingular solutions; Wormholes |
| Abstract |
We consider static spherically symmetric configurations in a Palatini extension of General Relativity including R-2 and Ricci-squared terms, which is known to replace the central singularity by a wormhole in the electrovacuum case. We modify the matter sector of the theory by adding to the usual Maxwell term a nonlinear electromagnetic extension which is known to implement a confinement mechanism in flat space. One feature of the resulting theory is that the nonlinear electric field leads to a dynamically generated cosmological constant. We show that with this matter source the solutions of the model are asymptotically de Sitter and possess a wormhole topology. We discuss in some detail the conditions that guarantee the absence of singularities and of traversable wormholes. |
| Address |
[Guendelman, E. I.; Vasihoun, M.] Ben Gurion Univ Negev, Dept Phys, IL-84105 Beer Sheva, Israel, Email: guendel@bgumail.bgu.ac.il; |
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Thesis |
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| Publisher |
Elsevier Science Bv |
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:000327907000045 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
1680 |
| Permanent link to this record |
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| Author |
Wang, D. |
| Title |
Model-independent traversable wormholes from baryon acoustic oscillations |
Type |
Journal Article |
| Year |
2023 |
Publication |
Physics of the Dark Universe |
Abbreviated Journal |
Phys. Dark Universe |
| Volume |
42 |
Issue |
|
Pages |
101306 - 8pp |
| Keywords |
Traversable wormholes; Dark energy; Baryon acoustic oscillations |
| Abstract |
In this paper, we investigate the model-independent traversable wormholes from baryon acoustic oscillations. Firstly, we place the statistical constraints on the average dark energy equation of state Wav by only using BAO data. Subsequently, two specific wormhole solutions are obtained, i.e, the cases of the constant redshift function and a special choice for the shape function. For the first case, we analyze the traversabilities of the wormhole configuration, and for the second case, we find that one can construct theoretically a traversable wormhole with infinitesimal amounts of average null energy condition violating phantom fluid. Furthermore, we perform the stability analysis for the first case, and find that the stable equilibrium configurations may increase for increasing values of the throat radius of the wormhole in the cases of a positive and a negative surface energy density. It is worth noting that the obtained wormhole solutions are static and spherically symmetrical metric, and that we assume Wav to be a constant between different redshifts when placing constraints, hence, these wormhole solutions can be interpreted as stable and static phantom wormholes configurations at some certain redshift which lies in the range [0.32, 2.34]. |
| Address |
[Wang, Deng] Univ Valencia, Inst Fis Corpuscular, CSIC, E-46980 Paterna, Spain, Email: cstar@nao.cas.cn |
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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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Abbreviated Series Title |
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Edition |
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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:001122744700001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5853 |
| Permanent link to this record |
