Home << 1 2 3 4 >>
List View
 | 
Citations
 | 
Details
   web
Records
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 (down) 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 Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes WOS:001126934800001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5857
Permanent link to this record
 
 
Author Balbinot, R.; Fabbri, A.
Title The Unruh Vacuum and the “In-Vacuum” in Reissner-Nordström Spacetime Type Journal Article
Year (down) 2024 Publication Universe Abbreviated Journal Universe
Volume 10 Issue 1 Pages 18 - 14pp
Keywords Hawking radiation; Unruh vacuum; Reissner-Nordstrom black holes
Abstract The Unruh vacuum is widely used as a quantum state to describe black hole evaporation since, near the horizon, it reproduces the physical state of a quantum field, the so-called “in-vacuum”, in the case where a black hole is formed by gravitational collapse. We examine the relation between these two quantum states in the background spacetime of a Reissner-Nordstrom black hole (both extremal and not), highlighting the similarities and striking differences.
Address [Balbinot, Roberto] Univ Bologna, Dipartimento Fis, Via Irnerio 46, I-40126 Bologna, Italy, Email: roberto.balbinot@unibo.it;
Corporate Author Thesis
Publisher Mdpi Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes WOS:001151025300001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5914
Permanent link to this record
 
 
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 (down) 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 Thesis
Publisher Mdpi Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes WOS:001256495600001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 6169
Permanent link to this record
 
 
Author Araujo Filho, A.A.; Jusufi, K.; Cuadros-Melgar, B.; Leon, G.
Title Dark matter signatures of black holes with Yukawa potential Type Journal Article
Year (down) 2024 Publication Physics of the Dark Universe Abbreviated Journal Phys. Dark Universe
Volume 44 Issue Pages 101500 - 20pp
Keywords Quantum-corrected Yukawa-like gravitational potential; Dark matter; Quasinormal frequencies; Black Holes shadows
Abstract This study uses a nonsingular Yukawa-modified potential to obtain a static and spherically symmetric black hole solution with a cosmological constant. Such Yukawa-like corrections are encoded in two parameters, alpha and lambda, that modify Newton's law of gravity in large distances, and a deformation parameter l(0), which plays an essential role in short distances. The most significant effect is encoded in alpha, which modifies the total black hole mass with an extra mass proportional to alpha M, mimicking the dark matter effects at large distances from the black hole. On the other hand, the effect due to lambda is small for astrophysical values. We scrutinize the quasinormal frequencies and shadows associated with a spherically symmetric black hole and the thermodynamical behavior influenced by the Yukawa potential. In particular, the thermodynamics of this black hole displays a rich behavior, including possible phase transitions. We use the WKB method to probe the quasinormal modes of massless scalar, electromagnetic, and gravitational field perturbations. In order to check the influence of the parameters on the shadow radius, we consider astrophysical data to determine their values, incorporating information on an optically thin radiating and infalling gas surrounding a black hole to model the black hole shadow image. In particular, we consider Sgr A* black hole as an example and we find that its shadow radius changes by order of 10(-9), meaning that the shadow radius of a black hole with Yukawa potential practically gives rise to the same result encountered in the Schwarzschild black hole. Also, in the eikonal regime, using astrophysical data for Yukawa parameters, we show that the value of the real part of the QNMs frequencies changes by 10(-18). Such Yukawa-like corrections are, therefore, difficult to measure by observations of gravitational waves using the current technology.
Address [Filhoa, A. A. Araujo] Univ Valencia, Ctr Mixto Univ Valencia, Dept Fis Teor, CSIC, Burjassot 46100, Valencia, Spain, Email: dilto@fisica.ufc.br;
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes WOS:001287415400001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 6226
Permanent link to this record
 
 
Author Ghedini, P.; Hajjar, R.; Mena, O.
Title Redshift-space distortions corner interacting dark energy Type Journal Article
Year (down) 2024 Publication Physics of the Dark Universe Abbreviated Journal Phys. Dark Universe
Volume 46 Issue Pages 101671 - 10pp
Keywords Dark energy; Dark matter; Dark sector interactions; Dark energy properties
Abstract Despite the fact that the Lambda CDM model has been highly successful over the last few decades in providing an accurate fit to a broad range of cosmological and astrophysical observations, different intriguing tensions and anomalies emerged at various statistical levels. Given the fact that the dark energy and the dark matter sectors remain unexplored, the answer to some of the tensions may rely on modifications of these two dark sectors. This manuscript explores the important role of the growth of structure in constraining non-standard cosmologies. In particular, we focus on the interacting dark energy (IDE) scenario, where dark matter and dark energy interact non-gravitationally. We aim to place constraints on the phenomenological parameters of these alternative models, by considering different datasets related to a number of cosmological measurements, to achieve a complementary analysis. A special emphasis is devoted to redshift-space distortion measurements (RSD), whose role in constraining beyond the standard paradigm models has not been recently highlighted. These observations indeed have a strong constraining power, rendering all parameters to their Lambda CDM canonical values, and therefore leaving little room for the IDE models explored here.
Address [Ghedini, Pietro] Univ Bologna, Dipartimento Fis & Astron, Via Irnerio 46, I-40126 Bologna, Italy, Email: pietro.ghedini3@studio.unibo.it;
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes WOS:001333958300001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 6298
Permanent link to this record
 
 
Author Araujo Filho, A.A.; Jusufi, K.; Cuadros-Melgar, B.; Leon, G.; Jawad, A.; Pellicer, C.E.
Title Charged black holes with Yukawa potential Type Journal Article
Year (down) 2024 Publication Physics of the Dark Universe Abbreviated Journal Phys. Dark Universe
Volume 46 Issue Pages 101711 - 16pp
Keywords Quantum-corrected Yukawa-like gravitational; potential; Dark matter; Charged black holes; Thermodynamic quantities; Quasinormal modes
Abstract This study derives a novel family of charged black hole solutions featuring short- and long-range modifications. These are achieved through a Yukawa-like gravitational potential modification and a nonsingular electric potential incorporation. The short-range corrections encode quantum gravity effects, while the long-range adjustments simulate gravitational effects akin to those attributed to dark matter. Our investigation reveals that the total mass of the black hole undergoes corrections owing to the apparent presence of dark matter mass and the self-adjusted electric charge mass. Two distinct solutions are discussed: a regular black hole solution characterizing small black holes, where quantum effects play a crucial role, and a second solution portraying large black holes at considerable distances, where the significance of Yukawa corrections comes into play. Notably, these long-range corrections contribute to an increase in the total mass and hold particular interest as they can emulate the role of dark matter. Finally, we explore the phenomenological aspects of the black hole. Specifically, we examine the influence of electric charge and Yukawa parameters on thermodynamic quantities, the quasinormal modes for the charged scalar perturbations as well as for the vector perturbations, analysis of the geodesics of light/massive particles, and the accretion of matter onto the charged black hole solution.
Address [Araujo, A. A.] Univ Valencia, Dept Fis Teor, Burjassot 46100, Valencia, Spain, Email: dilto@fisica.ufc.br;
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes WOS:001353676600001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 6337
Permanent link to this record
 
 
Author Real, D.; Calvo, D.
Title Silicon Photomultipliers for Neutrino Telescopes Type Journal Article
Year (down) 2023 Publication Universe Abbreviated Journal Universe
Volume 9 Issue 7 Pages 326 - 14pp
Keywords silicon photomultipliers; neutrino telescopes; time to digital converters; electronics acquisition
Abstract Neutrino astronomy has opened a new window to the extreme Universe, entering into a fruitful era built upon the success of neutrino telescopes, which have already given a new step forward in this novel and growing field by the first observation of steady point-like sources already achieved by IceCube. Neutrino telescopes equipped with Silicon PhotoMultipliers (SiPMs) will significantly increase in number, because of their excellent time resolution and the angular resolution, and will be in better condition to detect more steady sources as well as the unexpected. The use of SiPMs represents a challenge to the acquisition electronics because of the fast signals as well as the high levels of dark noise produced by SiPMs. The acquisition electronics need to include a noise rejection scheme by implementing a coincidence filter between channels. This work discusses the advantages and disadvantages of using SiPMs for the next generation of neutrino telescopes, focusing on the possible developments that could help for their adoption in the near future.
Address [Real, Diego; Calvo, David] Univ Valencia, Inst Fis Corpuscular, CSIC, IFIC, C Catedrat Jose Beltran 2, Valencia 46980, Spain, Email: real@ific.uv.es
Corporate Author Thesis
Publisher Mdpi Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes WOS:001038900800001 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 5593
Permanent link to this record
 
 
Author Gariazzo, S.; Mena, O.; Schwetz, T.
Title Quantifying the tension between cosmological and terrestrial constraints on neutrino masses Type Journal Article
Year (down) 2023 Publication Physics of the Dark Universe Abbreviated Journal Phys. Dark Universe
Volume 40 Issue Pages 101226 - 8pp
Keywords Neutrino masses; Neutrino mass ordering; Neutrino oscillations; Cosmological measurements of neutrino; masses
Abstract The sensitivity of cosmology to the total neutrino mass scale E m & nu; is approaching the minimal values required by oscillation data. We study quantitatively possible tensions between current and forecasted cosmological and terrestrial neutrino mass limits by applying suitable statistical tests such as Bayesian suspiciousness, parameter goodness-of-fit tests, or a parameter difference test. In particular, the tension will depend on whether the normal or the inverted neutrino mass ordering is assumed. We argue, that it makes sense to reject inverted ordering from the cosmology/oscillation comparison only if data are consistent with normal ordering. Our results indicate that, in order to reject inverted ordering with this argument, an accuracy on the sum of neutrino masses & sigma;(m & nu;) of better than 0.02 eV would be required from future cosmological observations.
Address [Gariazzo, Stefano] Ist Nazl Fis Nucl INFN, Sez Torino, Via P Giuria 1, I-10125 Turin, Italy, Email: gariazzo@to.infn.it
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes WOS:001042929800001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5623
Permanent link to this record
 
 
Author Araujo Filho, A.A.; Furtado, J.; Hassanabadi, H.; Reis, J.A.A.S.
Title Thermal analysis of photon-like particles in rainbow gravity Type Journal Article
Year (down) 2023 Publication Physics of the Dark Universe Abbreviated Journal Phys. Dark Universe
Volume 42 Issue Pages 101310 - 8pp
Keywords Rainbow gravity; Thermodynamics; Bounds
Abstract This work is devoted to study the thermodynamic behavior of photon-like particles within the rainbow gravity formalism. To to do this, we chose two particular ansatzs to accomplish our calculations. First, we consider a dispersion relation which avoids UV divergences, getting a positive effective cosmological constant. We provide numerical analysis for the thermodynamic functions of the system and bounds are estimated. Furthermore, a phase transition is also expected for this model. Second, we consider a dispersion relation employed in the context of Gamma Ray Bursts. Remarkably, for this latter case, the thermodynamic properties are calculated in an analytical manner and they turn out to depend on the harmonic series Hn, gamma & UGamma; (z), polygamma & psi;n(z) and zeta Riemann functions & zeta;(z).
Address [Araujo Filho, A. A.] Univ Valencia, CSIC, Dept Fis Teor & IFIC, Ctr Mixto Univ Valencia, Valencia 46100, Spain, Email: dilto@fisica.ufc.br;
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes WOS:001062674000001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5667
Permanent link to this record
 
 
Author Davesne, D.; Pastore, A.; Navarro, J.
Title Hartree-Fock Calculations in Semi-Infinite Matter with Gogny Interactions Type Journal Article
Year (down) 2023 Publication Universe Abbreviated Journal Universe
Volume 9 Issue 9 Pages 398 - 11pp
Keywords Nuclear Density Functional Theory; semi-infinite nuclear matter; Hartree-Fock equations; 21.60.Jz; 21.65.-f; 21.65.Mn
Abstract Hartree-Fock equations in semi-infinite nuclear matter for finite range Gogny interactions are presented together with a detailed numerical scheme to solve them. The value of the surface energy is then extracted and given for standard Gogny interactions.
Address [Davesne, Dany] Univ Lyon 1, Inst Phys Infinis Lyon 2, CNRS, IN2P3, 43 Bd 11 Novembre 1918, F-69622 Villeurbanne, France, Email: davesne@ipnl.in2p3.fr;
Corporate Author Thesis
Publisher Mdpi Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes WOS:001074530100001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5693
Permanent link to this record