Article
Physics, Particles & Fields
Monserrat Aguayo, Ankai Hernandez, Jose Mena, Julio Oliva, Marcelo Oyarzo
Summary: In this paper, a new family of black holes and solitons is identified, which allows for exact integration of scalar probes even with a non-minimal coupling with the Ricci scalar. The discrete modes on these geometries are independent of the radius of the black hole and can be integrated using hypergeometric functions to obtain exact expressions for the frequencies.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Astronomy & Astrophysics
Zhen Li
Summary: Black holes serve as a natural laboratory for the study of particle physics and astrophysics. This study focuses on a newly proposed rotating regular black hole and investigates the behavior of a massive scalar field near it. The research examines how this nonsingular spacetime affects the superradiance instability and quasinormal modes of the scalar field. The results show excellent agreement with previous research in the Kerr limit and provide insights into the effects of black hole spin, regularity, and scalar field mass on the quasinormal modes.
Article
Astronomy & Astrophysics
Edgardo Franzin, Stefano Liberati, Jacopo Mazza, Ramit Dey, Sumanta Chakraborty
Summary: This study investigates scalar test-field perturbations on a Kerr-black-bounce background, exploring rotating regular black holes and/or rotating traversable wormholes. The research confirms the stability of regular black holes and identifies a set of growing modes that render traversable wormholes unstable.
Article
Physics, Multidisciplinary
Chen Ma, Yu Zhang, Qian Li, Zhi-Wen Lin
Summary: The study shows that the real part of quasinormal frequency increases and the imaginary part decreases with an increase in magnetic charge or angular harmonic index. Magnetic charges reduce the damping of scalar perturbation but increase the frequency. The absorption cross-section of the scalar field in a black hole decreases as the magnetic charge increases, weakening the black hole's absorption capacity. The total absorption cross-section's high-frequency limit is the area of the black hole shadow.
COMMUNICATIONS IN THEORETICAL PHYSICS
(2022)
Article
Physics, Multidisciplinary
S. Habib Mazharimousavi
Summary: Exact solutions are important in understanding general relativity and other physical theories. The Einstein-Scalar theory provides an exact class of solutions with a specific potential and thermal stability.
Article
Astronomy & Astrophysics
Georgios Antoniou, Antoine Lehebel, Giulia Ventagli, Thomas P. Sotiriou
Summary: This paper studies the role of couplings in black hole scalarization and shows that the Ricci coupling plays a significant role in the properties of scalarized solutions and their domain of existence.
Article
Astronomy & Astrophysics
Yang Li, Yan-Gang Miao
Summary: Using the complex angular momentum method, we calculate the absorption cross section by analyzing a massless test scalar field around conformally related black holes. We find that the oscillation part of the absorption cross sections depends on the scale factor of conformal transformations and demonstrate substantial differences in absorption behavior between a regular black hole and a singular one using the conformally related Schwarzschild-Tangherlini black hole as an example. Our study provides a new approach to distinguish between regular and singular black holes.
Article
Astronomy & Astrophysics
Chengjia Chen, Qiyuan Pan, Jiliang Jing
Summary: In this study, we analytically investigate the quasinormal modes of a scalar perturbation around a rotating BTZ-like black hole in the Einstein-bumblebee gravity. It is observed that the Lorentz symmetry breaking parameter is only manifested in the imaginary parts of the quasinormal frequencies. The perturbational field decays faster for negative parameter values, but slower for positive ones. Furthermore, the study also reveals that the Lorentz symmetry breaking parameter enhances the conformal weights of operators dual to the scalar field in the boundary.
Article
Astronomy & Astrophysics
Alejandro Aguilar-Nieto, Victor Jaramillo, Juan Barranco, Argelia Bernal, Juan Carlos Degollado, Dario Nunez
Summary: In this study, the effect of self-interaction on the distribution and lifetime of long-lived configurations of massive scalar fields around black holes is analyzed. The spatial distribution of quasistationary states may be larger when there is self-interaction compared to the noninteracting case. The contribution of self-interaction to the lifetime of the configurations is found to be subdominant.
Article
Astronomy & Astrophysics
Jamie Bamber, Katy Clough, Pedro G. Ferreira, Lam Hui, Macarena Lagos
Summary: The study focuses on the behavior of scalar fields around compact objects and the growth of scalar clouds, revealing the mass and angular momentum growth of scalar clouds under different conditions, and analyzing the spatial distribution of scalars around black holes. The results also indicate the potential for accreted clouds to generate monochromatic gravitational wave signals similar to those from superradiant clouds, although with significantly weaker amplitudes.
Article
Physics, Multidisciplinary
L. A. Lopez, Valeria Ramirez
Summary: In this contribution, the quasi-normal modes of a regular black hole with a magnetic charge in nonlinear electrodynamics are studied, considering scalar and electromagnetic perturbations. The Generic-class, which includes the Bardeen-class, Hayward-class, and New-class solutions, can represent a black hole with two horizons or one horizon. First, the critical values of the magnetic charge and mass are obtained; Then, using the third-order WKB approximation, the dependence of the quasi-normal modes on the parameters of the Generic-class is determined. Finally, the transmission and reflection coefficients of the scattered wave in the third-order WKB approximation are calculated.
EUROPEAN PHYSICAL JOURNAL PLUS
(2023)
Article
Astronomy & Astrophysics
Marco Calza
Summary: We study the evaporation of a regular rotating black hole under the Hawking emission of a single scalar field. The black hole is described by the Kerr-black-bounce metric with a nearly extremal regularizing parameter l = 0.99r+. We compare the results with a Kerr black hole evaporating under the same conditions. Our findings show that the regular black hole evolves to a non-Schwarzschild-like state with a slightly different asymptotic spin compared to a Kerr black hole. We also discuss how the surface gravity affects the temperature and primary emissivity, resulting in a longer lifetime for the regular black hole. Finally, we briefly comment on the possibility of investigating the beyond-the-horizon structure of a black hole through its Hawking emission.
Article
Astronomy & Astrophysics
Filipe Moura, Joao Rodrigues
Summary: In this study, we calculated the quasinormal frequencies of d-dimensional spherically symmetric black holes with leading string alpha' corrections for tensorial gravitational perturbations and scalar test fields. We found that, in contrast to Einstein gravity, the real parts of the frequency are no longer equal for these two cases, but the corresponding imaginary parts remain equal to the principal Lyapunov exponent corresponding to circular null geodesics.
Article
Astronomy & Astrophysics
Mohsen Khodadi, Reza Pourkhodabakhshi
Summary: The study examines the impact of a novel rotating black hole on the timescale of scalar cloud formation, showing that including a regularization length scale l can shorten the formation time. This reduction in instability growth time improves the prospects for phenomenological detection of new physics.
Article
Physics, Multidisciplinary
Ahmad Al-Badawi, Sara Kanzi, Izzet Sakalli
Summary: This study focuses on the spinorial wave equations and greybody radiation in the NUT black hole spacetime. By using the Newman-Penrose formalism, the Dirac equation in NUT spacetime is analyzed, separating it into radial and angular components to discuss associated solutions and potentials. Additionally, the Klein-Gordon equation is studied to compute greybody factors, with a detailed investigation into the impact of the NUT parameter on the spacetime's greybody factors.
EUROPEAN PHYSICAL JOURNAL PLUS
(2022)
