Analytic and asymptotically flat hairy (ultra-compact) black-hole solutions and their axial perturbations
Abstract In this work, we consider a very simple gravitational theory that contains a scalar field with its kinetic and potential terms minimally coupled to gravity, while the scalar field is assumed to have a coulombic form. In the context of this theory, we study an analytic, asymptotically flat,...
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| Format: | Article |
| Language: | English |
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SpringerOpen
2022-04-01
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| Series: | Journal of High Energy Physics |
| Subjects: | |
| Online Access: | https://doi.org/10.1007/JHEP04(2022)096 |
| _version_ | 1797865800840773632 |
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| author | Athanasios Bakopoulos Theodoros Nakas |
| author_facet | Athanasios Bakopoulos Theodoros Nakas |
| author_sort | Athanasios Bakopoulos |
| collection | DOAJ |
| description | Abstract In this work, we consider a very simple gravitational theory that contains a scalar field with its kinetic and potential terms minimally coupled to gravity, while the scalar field is assumed to have a coulombic form. In the context of this theory, we study an analytic, asymptotically flat, and regular (ultra-compact) black-hole solutions with non-trivial scalar hair of secondary type. At first, we examine the properties of the static and spherically symmetric black-hole solution — firstly appeared in [109] — and we find that in the causal region of the spacetime the stress-energy tensor, needed to support our solution, satisfies the strong energy conditions. Then, by using the slow-rotating approximation, we generalize the static solution into a slowly rotating one, and we determine explicitly its angular velocity ω(r). We also find that the angular velocity of our ultra-compact solution is always larger compared to the angular velocity of the corresponding equally massive slow-rotating Schwarzschild black hole. In addition, we investigate the axial perturbations of the derived solutions by determining the Schrödinger-like equation and the effective potential. We show that there is a region in the parameter space of the free parameters of our theory, which allows for the existence of stable ultra-compact black hole solutions. Specifically, we calculate that the most compact and stable black hole solution is 0.551 times smaller than the Schwarzschild one, while it rotates 2.491 times faster compared to the slow-rotating Schwarzschild black hole. Finally, we present without going into details the generalization of the derived asymptotically flat solutions to asymptotically (A)dS solutions. |
| first_indexed | 2024-04-09T23:14:21Z |
| format | Article |
| id | doaj.art-a2e64617cc114f4885e8cfd72b3ec724 |
| institution | Directory Open Access Journal |
| issn | 1029-8479 |
| language | English |
| last_indexed | 2024-04-09T23:14:21Z |
| publishDate | 2022-04-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Journal of High Energy Physics |
| spelling | doaj.art-a2e64617cc114f4885e8cfd72b3ec7242023-03-22T10:11:20ZengSpringerOpenJournal of High Energy Physics1029-84792022-04-012022413310.1007/JHEP04(2022)096Analytic and asymptotically flat hairy (ultra-compact) black-hole solutions and their axial perturbationsAthanasios Bakopoulos0Theodoros Nakas1Division of Theoretical Physics, Department of Physics, University of IoanninaDivision of Theoretical Physics, Department of Physics, University of IoanninaAbstract In this work, we consider a very simple gravitational theory that contains a scalar field with its kinetic and potential terms minimally coupled to gravity, while the scalar field is assumed to have a coulombic form. In the context of this theory, we study an analytic, asymptotically flat, and regular (ultra-compact) black-hole solutions with non-trivial scalar hair of secondary type. At first, we examine the properties of the static and spherically symmetric black-hole solution — firstly appeared in [109] — and we find that in the causal region of the spacetime the stress-energy tensor, needed to support our solution, satisfies the strong energy conditions. Then, by using the slow-rotating approximation, we generalize the static solution into a slowly rotating one, and we determine explicitly its angular velocity ω(r). We also find that the angular velocity of our ultra-compact solution is always larger compared to the angular velocity of the corresponding equally massive slow-rotating Schwarzschild black hole. In addition, we investigate the axial perturbations of the derived solutions by determining the Schrödinger-like equation and the effective potential. We show that there is a region in the parameter space of the free parameters of our theory, which allows for the existence of stable ultra-compact black hole solutions. Specifically, we calculate that the most compact and stable black hole solution is 0.551 times smaller than the Schwarzschild one, while it rotates 2.491 times faster compared to the slow-rotating Schwarzschild black hole. Finally, we present without going into details the generalization of the derived asymptotically flat solutions to asymptotically (A)dS solutions.https://doi.org/10.1007/JHEP04(2022)096Black HolesSpacetime Singularities |
| spellingShingle | Athanasios Bakopoulos Theodoros Nakas Analytic and asymptotically flat hairy (ultra-compact) black-hole solutions and their axial perturbations Journal of High Energy Physics Black Holes Spacetime Singularities |
| title | Analytic and asymptotically flat hairy (ultra-compact) black-hole solutions and their axial perturbations |
| title_full | Analytic and asymptotically flat hairy (ultra-compact) black-hole solutions and their axial perturbations |
| title_fullStr | Analytic and asymptotically flat hairy (ultra-compact) black-hole solutions and their axial perturbations |
| title_full_unstemmed | Analytic and asymptotically flat hairy (ultra-compact) black-hole solutions and their axial perturbations |
| title_short | Analytic and asymptotically flat hairy (ultra-compact) black-hole solutions and their axial perturbations |
| title_sort | analytic and asymptotically flat hairy ultra compact black hole solutions and their axial perturbations |
| topic | Black Holes Spacetime Singularities |
| url | https://doi.org/10.1007/JHEP04(2022)096 |
| work_keys_str_mv | AT athanasiosbakopoulos analyticandasymptoticallyflathairyultracompactblackholesolutionsandtheiraxialperturbations AT theodorosnakas analyticandasymptoticallyflathairyultracompactblackholesolutionsandtheiraxialperturbations |