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Author Casals, M.; Fabbri, A.; Martinez, C.; Zanelli, J. url  doi
openurl 
  Title (up) Quantum dress for a naked singularity Type Journal Article
  Year 2016 Publication Physics Letters B Abbreviated Journal Phys. Lett. B  
  Volume 760 Issue Pages 244-248  
  Keywords Semiclassical gravity; Quantum backreaction; Cosmic censorship; Black holes; Naked singularities; BTZ  
  Abstract We investigate semiclassical backreaction on a conical naked singularity space-time with a negative cosmological constant in (2 + 1)-dimensions. In particular, we calculate the renormalized quantum stress-energy tensor for a conformally coupled scalar field on such naked singularity space-time. We then obtain the backreacted metric via the semiclassical Einstein equations. We show that, in the regime where the semiclassical approximation can be trusted, backreaction dresses the naked singularity with an event horizon, thus enforcing (weak) cosmic censorship.  
  Address [Casals, Marc] Ctr Brasileiro Pesquisas Fis, BR-22290180 Rio De Janeiro, Brazil, Email: mcasals@cbpf.br;  
  Corporate Author Thesis  
  Publisher Elsevier Science Bv Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0370-2693 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000382890500037 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2804  
Permanent link to this record
 
 
Author Boudet, S.; Bombacigno, F.; Olmo, G.J.; Porfirio, P. url  doi
openurl 
  Title (up) Quasinormal modes of Schwarzschild black holes in projective invariant Chern-Simons modified gravity Type Journal Article
  Year 2022 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.  
  Volume 05 Issue 5 Pages 032 - 29pp  
  Keywords Gauss-Bonnet-Lovelock-Horndeski-Palatini etc gravity theories; Exact solutions; black holes and black hole thermodynamics in GR and beyond  
  Abstract We generalize the Chern-Simons modified gravity to the metric-affine case and impose projective invariance by supplementing the Pontryagin density with homothetic curvature terms which do not spoil topologicity. The latter is then broken by promoting the coupling of the Chern-Simons term to a (pseudo)-scalar field. The solutions for torsion and nonmetricity are derived perturbatively, showing that they can be iteratively obtained from the background fields. This allows us to describe the dynamics for the metric and the scalar field perturbations in a self-consistent way, and we apply the formalism to the study of quasi normal modes in a Schwarzschild black hole background. Unlike in the metric formulation of this theory, we show that the scalar field is endowed with dynamics even in the absence of its kinetic term in the action. Finally, using numerical methods we compute the quasinormal frequencies and characterize the late-time power law tails for scalar and metric perturbations, comparing the results with the outcomes of the purely metric approach.  
  Address [Boudet, S.] Univ Trento, Dipartimento Fis, Via Sommar 14, I-38123 Povo, TN, Italy, Email: simon.boudet@unitn.it;  
  Corporate Author Thesis  
  Publisher IOP Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1475-7516 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000804493000004 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5238  
Permanent link to this record
 
 
Author Guerrero, M.; Mora-Perez, G.; Olmo, G.J.; Orazi, E.; Rubiera-Garcia, D. url  doi
openurl 
  Title (up) Rotating black holes in Eddington-inspired Born-Infeld gravity: an exact solution Type Journal Article
  Year 2020 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.  
  Volume 07 Issue 7 Pages 058 - 31pp  
  Keywords modified gravity; GR black holes; Wormholes  
  Abstract We find an exact, rotating charged black hole solution within Eddington-inspired Born-Infeld gravity. To this end we employ a recently developed correspondence or mapping between modified gravity models built as scalars out of contractions of the metric with the Ricci tensor, and formulated in metric-affine spaces (Ricci-Based Gravity theories) and General Relativity. This way, starting from the Kerr-Newman solution, we show that this mapping bring us the axisymmetric solutions of Eddington-inspired Born-Infeld gravity coupled to a certain model of non-linear electrodynamics. We discuss the most relevant physical features of the solutions obtained this way, both in the spherically symmetric limit and in the fully rotating regime. Moreover, we further elaborate on the potential impact of this important technical progress for bringing closer the predictions of modified gravity with the astrophysical observations of compact objects and gravitational wave astronomy.  
  Address [Guerrero, Merce; Rubiera-Garcia, Diego] Univ Complutense Madrid, Dept Fis Teor, E-28040 Madrid, Spain, Email: merguerr@ucm.es;  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1475-7516 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000609085900005 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4682  
Permanent link to this record
 
 
Author ATLAS Collaboration (Aad, G. et al); Amoros, G.; Cabrera Urban, S.; Castillo Gimenez, V.; Costa, M.J.; Escobar, C.; Ferrer, A.; Fiorini, L.; Fuster, J.; Garcia, C.; Gonzalez de la Hoz, S.; Hernandez Jimenez, Y.; Higon-Rodriguez, E.; Irles Quiles, A.; Kaci, M.; Lacasta, C.; Lacuesta, V.R.; Marti-Garcia, S.; Miñano, M.; Mitsou, V.A.; Moles-Valls, R.; Moreno Llacer, M.; Oliver Garcia, E.; Perez Garcia-Estañ, M.T.; Ros, E.; Salt, J.; Solans, C.A.; Soldevila, U.; Sanchez, J.; Torro Pastor, E.; Valladolid Gallego, E.; Valls Ferrer, J.A.; Villaplana Perez, M.; Vos, M.; Wildauer, A. url  doi
openurl 
  Title (up) Search for strong gravity signatures in same-sign dimuon final states using the ATLAS detector at the LHC Type Journal Article
  Year 2012 Publication Physics Letters B Abbreviated Journal Phys. Lett. B  
  Volume 709 Issue 4-5 Pages 322-340  
  Keywords LHC; ATLAS; Microscopic black holes; Extra dimensions; Same-sign dimuons  
  Abstract A search for microscopic black holes has been performed in a same-sign dimuon final state using 1.3 fb(-1) of proton-proton collision data collected with the ATLAS detector at a centre of mass energy of 7 TeV at the CERN Large Hadron Collider. The data are found to be consistent with the expectation from the Standard Model and the results are used to derive exclusion contours in the context of a low scale gravity model.  
  Address [Aad, G.; Ahles, F.; Bernhard, R.; Bitenc, U.; Bruneliere, R.; Caron, S.; Christov, A.; Consorti, V.; Fehling-Kaschek, M.; Flechl, M.; Glatzer, J.; Hartert, J.; Herten, G.; Horner, S.; Jakobs, K.; Kollefrath, M.; Kononov, A. I.; Kuehn, S.; Lai, S.; Landgraf, U.; Lohwasser, K.; Ludwig, I.; Ludwig, J.; Lumb, D.; Mahboubi, K.; Mohr, W.; Nilsen, H.; Parzefall, U.; Rammensee, M.; Runge, K.; Rurikova, Z.; Schmidt, E.; Schumacher, M.; Siegert, F.; Stoerig, K.; Sundermann, J. E.; Temming, K. K.; Thoma, S.; Tobias, J.; Tsiskaridze, V.; Venturi, M.; Vivarelli, I.; von Radziewski, H.; Warsinsky, M.; Weiser, C.; Werner, M.; Wiik, L. A. M.; Winkelmann, S.; Xie, S.; Zimmermann, S.] Univ Freiburg, Fak Math & Phys, D-79106 Freiburg, Germany  
  Corporate Author Thesis  
  Publisher Elsevier Science Bv Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0370-2693 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000302454700003 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 976  
Permanent link to this record
 
 
Author Lobo, F.S.N.; Olmo, G.J.; Rubiera-Garcia, D. url  doi
openurl 
  Title (up) Semiclassical geons as solitonic black hole remnants Type Journal Article
  Year 2013 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.  
  Volume 07 Issue 7 Pages 011 - 10pp  
  Keywords modified gravity; primordial black holes; Wormholes; quantum field theory on curved space  
  Abstract We find that the end state of black hole evaporation could be represented by non-singular and without event horizon stable solitonic remnants with masses of the order the Planck scale and up to similar to 16 units of charge. Though these objects are locally indistinguishable from spherically symmetric, massive electric (or magnetic) charges, they turn out to be sourceless geons containing a wormhole generated by the electromagnetic field. Our results are obtained by interpreting semiclassical corrections to Einstein's theory in the first-order (Palatini) formalism, which yields second-order equations and avoids the instabilities of the usual (metric) formulation of quadratic gravity. We also discuss the potential relevance of these solutions for primordial black holes and the dark matter problem.  
  Address [Lobo, Francisco S. N.] Univ Lisbon, Ctr Astron & Astrofis, P-1749016 Lisbon, Portugal, Email: flobo@cii.fc.ul.pt;  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1475-7516 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000322582000012 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1532  
Permanent link to this record
 
 
Author Olmo, G.J.; Rubiera-Garcia, D. url  doi
openurl 
  Title (up) 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 Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1475-7516 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000332711400010 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1733  
Permanent link to this record
 
 
Author Guerrero, M.; Olmo, G.J.; Rubiera-Garcia, D.; Saez-Chillon Gomez, D. url  doi
openurl 
  Title (up) Shadows and optical appearance of black bounces illuminated by a thin accretion disk Type Journal Article
  Year 2021 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.  
  Volume 08 Issue 8 Pages 036 - 19pp  
  Keywords GR black holes; Wormholes; modified gravity; accretion  
  Abstract We study the light rings and shadows of an uniparametric family of spherically symmetric geometries interpolating between the Schwarzschild solution, a regular black hole, and a traversable wormhole, and dubbed as black bounces, all of them sharing the same critical impact parameter. We consider the ray-tracing method in order to study the impact parameter regions corresponding to the direct, lensed, and photon ring emissions, finding a broadening of all these regions for black bounce solutions as compared to the Schwarzschild one. Using this, we determine the optical appearance of black bounces when illuminated by three standard toy models of optically and geometrically thin accretion disks viewed in face-on orientation.  
  Address [Guerrero, Merce; Rubiera-Garcia, Diego] Univ Complutense Madrid, Dept Fis Teor, E-28040 Madrid, Spain, Email: merguerr@ucm.es;  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1475-7516 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000686656000022 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4943  
Permanent link to this record
 
 
Author Olmo, G.J.; Rosa, J.L.; Rubiera-Garcia, D.; Saez-Chillon Gomez, D. url  doi
openurl 
  Title (up) Shadows and photon rings of regular black holes and geonic horizonless compact objects Type Journal Article
  Year 2023 Publication Classical and Quantum Gravity Abbreviated Journal Class. Quantum Gravity  
  Volume 40 Issue 17 Pages 174002 - 37pp  
  Keywords black holes; compact objects; photon rings; shadows; metric-affine gravity; Born-Infeld gravity; regular solutions  
  Abstract The optical appearance of a body compact enough to feature an unstable bound orbit, when surrounded by an accretion disk, is expected to be dominated by a luminous ring of radiation enclosing a central brightness depression typically known as the shadow. Despite observational limitations, the rough details of this picture have been now confirmed by the results of the Event Horizon Telescope (EHT) Collaboration on the imaging of the M87 and Milky Way supermassive central objects. However, the precise characterization of both features-ring and shadow-depends on the interaction between the background geometry and the accretion disk, thus being a fertile playground to test our theories on the nature of compact objects and the gravitational field itself in the strong-field regime. In this work we use both features in order to test a continuous family of solutions interpolating between regular black holes and horizonless compact objects, which arise within the Eddington-inspired Born-Infeld theory of gravity, a viable extension of Einstein's general relativity (GR). To this end we consider seven distinctive classes of such configurations (five black holes and two traversable wormholes) and study their optical appearances under illumination by a geometrically and optically thin accretion disk, emitting monochromatically with three analytic intensity profiles previously suggested in the literature. We build such images and consider the sub-ring structure created by light rays crossing the disk more than once and existing on top of the main ring of radiation. We discuss in detail the modifications as compared to their GR counterparts, the Lyapunov exponents of unstable nearly-bound orbits, as well as the differences between black hole and traversable wormholes for the three intensity profiles. In addition we use the claim by the EHT Collaboration on the radius of the bright ring acting (under proper calibrations) as a proxy for the radius of the shadow itself to explore the parameter space of our solutions compatible with such a result.  
  Address [Olmo, Gonzalo J.] Univ Valencia, Ctr Mixto Univ Valencia, Dept Fis Teor, CSIC, Burjassot 46100, Valencia, Spain, Email: drubiera@ucm.es  
  Corporate Author Thesis  
  Publisher IOP Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0264-9381 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:001043720300001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5600  
Permanent link to this record
 
 
Author De Romeri, V.; Martinez-Mirave, P.; Tortola, M. url  doi
openurl 
  Title (up) Signatures of primordial black hole dark matter at DUNE and THEIA Type Journal Article
  Year 2021 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.  
  Volume 10 Issue 10 Pages 051 - 21pp  
  Keywords dark matter theory; neutrino experiments; primordial black holes  
  Abstract Primordial black holes (PBHs) are a potential dark matter candidate whose masses can span over many orders of magnitude. If they have masses in the 10(15)-10(17) g range, they can emit sizeable fluxes of MeV neutrinos through evaporation via Hawking radiation. We explore the possibility of detecting light (non-)rotating PBHs with future neutrino experiments. We focus on two next generation facilities: the Deep Underground Neutrino Experiment (DUNE) and THEIA. We simulate the expected event spectra at both experiments assuming different PBH mass distributions and spins, and we extract the expected 95% C.L. sensitivities to these scenarios. Our analysis shows that future neutrino experiments like DUNE and THEIA will be able to set competitive constraints on PBH dark matter, thus providing complementary probes in a part of the PBH parameter space currently constrained mainly by photon data.  
  Address [De Romeri, Valentina] Univ Valencia, Dept Fis Teor, Paterna 46980, Spain, Email: deromeri@ific.uv.es;  
  Corporate Author Thesis  
  Publisher IOP Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1475-7516 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000758221400007 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 5140  
Permanent link to this record
 
 
Author Galli, P.; Meessen, P.; Ortin, T. url  doi
openurl 
  Title (up) 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 Thesis  
  Publisher Springer Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1029-8479 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000321374400011 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 1555  
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