Quasinormal modes of three $$(2+1)$$ ( 2 + 1 ) -dimensional black holes in string theory, conformal gravity, and Hu–Sawicki F(R) theory via the Heun function

Abstract We study the propagation of massless fermionic fields, implementing a family of special functions: Heun functions, in solving the wave equation in three three-dimensional backgrounds, including the BTZ black hole in string theory and Lifshitz black hole solutions in conformal gravity and Hu...

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Main Authors: F. Naderi, A. Rezaei-Aghdam
Format: Article
Language:English
Published: SpringerOpen 2024-12-01
Series:European Physical Journal C: Particles and Fields
Online Access:https://doi.org/10.1140/epjc/s10052-024-13655-z
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author F. Naderi
A. Rezaei-Aghdam
author_facet F. Naderi
A. Rezaei-Aghdam
author_sort F. Naderi
collection DOAJ
description Abstract We study the propagation of massless fermionic fields, implementing a family of special functions: Heun functions, in solving the wave equation in three three-dimensional backgrounds, including the BTZ black hole in string theory and Lifshitz black hole solutions in conformal gravity and Hu–Sawicki F(R) theory. The main properties of the selected black hole solutions is that their line elements are Weyl related to that of a homogeneous spacetime, whose spatial part possesses Lie symmetry, described by Lobachevsky-type geometry with arbitrary negative Gaussian curvature. Using the Weyl symmetry of massless Dirac action, we consider the perturbation equations of fermionic fields in relation to those of the homogeneous background, which having definite singularities, are transformed into Heun’s equation. We point out the existence of quasinormal modes labeled by the accessory parameter of the Heun function. The distribution of the quasinormal modes has been clarified to satisfy the boundary conditions that require ingoing and decaying waves at the event horizon and conformal infinity, respectively. It turned out that the procedure based on the Heun function, beside reproducing the previously known results obtained via hypergeometric function for the BTZ and Lifshitz black hole solution in conformal gravity, brings up new families of quasinormal frequencies, which can also contain purely imaginary modes. Also, the analysis of the quasinormal modes shows that with the negative imaginary part of complex frequencies $$\omega =\omega _{Re}+i\omega _{Im}$$ ω = ω Re + i ω Im , the fermionic perturbations are stable in this background.
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spelling doaj-art-4b37eb5e4ce44a23b785145415f9ecfd2025-02-02T12:39:40ZengSpringerOpenEuropean Physical Journal C: Particles and Fields1434-60522024-12-01841211410.1140/epjc/s10052-024-13655-zQuasinormal modes of three $$(2+1)$$ ( 2 + 1 ) -dimensional black holes in string theory, conformal gravity, and Hu–Sawicki F(R) theory via the Heun functionF. Naderi0A. Rezaei-Aghdam1Department of Physics, Faculty of Basic Sciences, Azarbaijan Shahid Madani UniversityDepartment of Physics, Faculty of Basic Sciences, Azarbaijan Shahid Madani UniversityAbstract We study the propagation of massless fermionic fields, implementing a family of special functions: Heun functions, in solving the wave equation in three three-dimensional backgrounds, including the BTZ black hole in string theory and Lifshitz black hole solutions in conformal gravity and Hu–Sawicki F(R) theory. The main properties of the selected black hole solutions is that their line elements are Weyl related to that of a homogeneous spacetime, whose spatial part possesses Lie symmetry, described by Lobachevsky-type geometry with arbitrary negative Gaussian curvature. Using the Weyl symmetry of massless Dirac action, we consider the perturbation equations of fermionic fields in relation to those of the homogeneous background, which having definite singularities, are transformed into Heun’s equation. We point out the existence of quasinormal modes labeled by the accessory parameter of the Heun function. The distribution of the quasinormal modes has been clarified to satisfy the boundary conditions that require ingoing and decaying waves at the event horizon and conformal infinity, respectively. It turned out that the procedure based on the Heun function, beside reproducing the previously known results obtained via hypergeometric function for the BTZ and Lifshitz black hole solution in conformal gravity, brings up new families of quasinormal frequencies, which can also contain purely imaginary modes. Also, the analysis of the quasinormal modes shows that with the negative imaginary part of complex frequencies $$\omega =\omega _{Re}+i\omega _{Im}$$ ω = ω Re + i ω Im , the fermionic perturbations are stable in this background.https://doi.org/10.1140/epjc/s10052-024-13655-z
spellingShingle F. Naderi
A. Rezaei-Aghdam
Quasinormal modes of three $$(2+1)$$ ( 2 + 1 ) -dimensional black holes in string theory, conformal gravity, and Hu–Sawicki F(R) theory via the Heun function
European Physical Journal C: Particles and Fields
title Quasinormal modes of three $$(2+1)$$ ( 2 + 1 ) -dimensional black holes in string theory, conformal gravity, and Hu–Sawicki F(R) theory via the Heun function
title_full Quasinormal modes of three $$(2+1)$$ ( 2 + 1 ) -dimensional black holes in string theory, conformal gravity, and Hu–Sawicki F(R) theory via the Heun function
title_fullStr Quasinormal modes of three $$(2+1)$$ ( 2 + 1 ) -dimensional black holes in string theory, conformal gravity, and Hu–Sawicki F(R) theory via the Heun function
title_full_unstemmed Quasinormal modes of three $$(2+1)$$ ( 2 + 1 ) -dimensional black holes in string theory, conformal gravity, and Hu–Sawicki F(R) theory via the Heun function
title_short Quasinormal modes of three $$(2+1)$$ ( 2 + 1 ) -dimensional black holes in string theory, conformal gravity, and Hu–Sawicki F(R) theory via the Heun function
title_sort quasinormal modes of three 2 1 2 1 dimensional black holes in string theory conformal gravity and hu sawicki f r theory via the heun function
url https://doi.org/10.1140/epjc/s10052-024-13655-z
work_keys_str_mv AT fnaderi quasinormalmodesofthree2121dimensionalblackholesinstringtheoryconformalgravityandhusawickifrtheoryviatheheunfunction
AT arezaeiaghdam quasinormalmodesofthree2121dimensionalblackholesinstringtheoryconformalgravityandhusawickifrtheoryviatheheunfunction