Final state of superradiant instability in Einstein-Maxwell-dilaton black hole
Abstract
This article examines the instability of charged black holes, using Einstein-Maxwell-dilaton theory and a massless charged scalar field. Our study demonstrates that these black holes become unstable in a certain range of frequencies, which causes scalar "hair" to form outside the event horizon. By using numerical integration on the coupled field equations, we show that there is a phase transition between a purely charged black hole and a hairy black hole configuration. The results show that the hairy phase appears when the temperature is less than TC, the critical temperature, whereas for T>TC, the system stays purely charged. Also, our findings show that the critical temperature increases with the size of the black hole, implying that the onset of the phase transition becomes progressively more difficult for larger horizons. Lastly, we see that the system enters a stable equilibrium at the critical temperature, which is the final state of the superradiant instability. These results provide us with useful information on how nonlinear superradiant events change and how scalarized black holes arise in more comprehensive theories of gravity.
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BibTeX
@misc{rahmani2026final,
title = {{Final state of superradiant instability in Einstein-Maxwell-dilaton black hole}},
author = {Afsaneh Rahmani and Samaneh Oghbaiee},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.04646},
eprint = {2611.04646},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.04646},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Final state of superradiant instability in Einstein-Maxwell-dilaton black hole
AU - Afsaneh Rahmani
AU - Samaneh Oghbaiee
PY - 2026
DA - 2026/11/03
PB - arXiv
DO - 10.48550/arxiv.2611.04646
UR - https://arxiv.org/abs/2611.04646
AB - This article examines the instability of charged black holes, using Einstein-Maxwell-dilaton theory and a massless charged scalar field. Our study demonstrates that these black holes become unstable in a certain range of frequencies, which causes scalar "hair" to form outside the event horizon. By using numerical integration on the coupled field equations, we show that there is a phase transition between a purely charged black hole and a hairy black hole configuration. The results show that the hairy phase appears when the temperature is less than T_C, the critical temperature, whereas for T>T_C, the system stays purely charged. Also, our findings show that the critical temperature increases with the size of the black hole, implying that the onset of the phase transition becomes progressively more difficult for larger horizons. Lastly, we see that the system enters a stable equilibrium at the critical temperature, which is the final state of the superradiant instability. These results provide us with useful information on how nonlinear superradiant events change and how scalarized black holes arise in more comprehensive theories of gravity.
ER -