Extremal Scalarization of Charged Black Holes: Miransky Scaling across Reissner-Nordström Extremality
Abstract
We study spontaneous scalarization near and at extremality in Einstein-Maxwell-scalar theory. As Reissner-Nordström (RN) extremality is approached from below, the nonextremal scalarization existence curves collapse toward a common critical threshold αc=1/4 given by the Breitenlohner-Freedman bound for the near-horizon throat (AdS2× S2) of its extremal black hole. For a polynomial coupling, we construct extremal black holes with nonconstant scalar hair, satisfying M2+Qs2=Q2, which places them in the overcharged region Q/M>1 beyond the RN bound. A common near-region phase mechanism predicts accumulation toward the RN extremality from both sides, yielding Miransky-type scaling. In the extremal sector, the logarithmic phase interval doubles, halving the exponent which denotes the geometric spacing of successive node scales.
Related
- Flexible numerical characteristic gluing to extremal Reissner-Nordström black holes
- Zero-damped modes of near-extremal Reissner--Nordström black holes from exact WKB
- Nonoscillatory gravitational quasinormal modes of Reissner–Nordström–de Sitter spacetime
- Reissner-Nordstrom in the Bertotti-Robinson-Bonnor-Melvin electromagnetic field
- Stochastic motion of massless particles near event horizons in Schwarzschild and Reissner-Nordström spacetimes
BibTeX
@misc{guo2026extremal,
title = {{Extremal Scalarization of Charged Black Holes: Miransky Scaling across Reissner-Nordström Extremality}},
author = {Hong Guo and Yun Soo Myung and Lijing Shao},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.20040},
eprint = {2609.20040},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.20040},
note = {CC BY-NC-SA 4.0},
}
RIS
TY - UNPB
TI - Extremal Scalarization of Charged Black Holes: Miransky Scaling across Reissner-Nordström Extremality
AU - Hong Guo
AU - Yun Soo Myung
AU - Lijing Shao
PY - 2026
DA - 2026/09/17
PB - arXiv
DO - 10.48550/arxiv.2609.20040
UR - https://arxiv.org/abs/2609.20040
AB - We study spontaneous scalarization near and at extremality in Einstein-Maxwell-scalar theory. As Reissner-Nordström (RN) extremality is approached from below, the nonextremal scalarization existence curves collapse toward a common critical threshold α_c=1/4 given by the Breitenlohner-Freedman bound for the near-horizon throat (AdS_2× S^2) of its extremal black hole. For a polynomial coupling, we construct extremal black holes with nonconstant scalar hair, satisfying M^2+Q_s^2=Q^2, which places them in the overcharged region Q/M>1 beyond the RN bound. A common near-region phase mechanism predicts accumulation toward the RN extremality from both sides, yielding Miransky-type scaling. In the extremal sector, the logarithmic phase interval doubles, halving the exponent which denotes the geometric spacing of successive node scales.
ER -