Schwinger stability of T-duality-inspired extremal black holes
Abstract
We study the near-horizon charged-scalar instability associated with Schwinger pair production in the charged regular black hole geometry of the zero-point-length T-duality prescription. Using the same effective geometry and regularized gauge potential, we construct the extremal branch, its AdS2 × S2 near-horizon throat, and the charged-scalar instability threshold for a general form factor. For the explicit T-duality form factor the extremal branch terminates at rext = √2 l0, where the extremal charge and the near-horizon electric field vanish while the AdS2 radius remains finite at √3 l0. At this endpoint the exact near-horizon instability parameter is negative. In the semiclassical regime the corresponding charge-to-mass threshold diverges as the endpoint is approached. Thus, for each fixed massive species with finite q/m, a sufficiently near-endpoint portion of the extremal branch is free of the local charged-scalar instability. For comparison, the Ayón-Beato-García (ABG) Einstein-nonlinear-electrodynamics solution has a nonvanishing extremal near-horizon electric field. For an additional minimally coupled charged-scalar probe, the corresponding local Schwinger threshold remains finite. Thus the divergent near-endpoint Schwinger barrier found in the T-duality branch is not a generic consequence of regularity.
Related
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- Extremal black hole mimickers: geometry, stability, and long-delay signal trains
- Schwinger--Keldysh worldline effective field theory for quantum black holes: dissipation, noise and decoherence
- Scalarized extremal black holes in the Einstein-Maxwell-scalar theory with two U(1) fields
- Extremal black hole throats from non extremal near horizon expansions
BibTeX
@misc{chen2026schwinger,
title = {{Schwinger stability of T-duality-inspired extremal black holes}},
author = {Chiang-Mei Chen and Kimet Jusufi and Douglas Singleton},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.18528},
eprint = {2609.18528},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.18528},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Schwinger stability of T-duality-inspired extremal black holes
AU - Chiang-Mei Chen
AU - Kimet Jusufi
AU - Douglas Singleton
PY - 2026
DA - 2026/09/16
PB - arXiv
DO - 10.48550/arxiv.2609.18528
UR - https://arxiv.org/abs/2609.18528
AB - We study the near-horizon charged-scalar instability associated with Schwinger pair production in the charged regular black hole geometry of the zero-point-length T-duality prescription. Using the same effective geometry and regularized gauge potential, we construct the extremal branch, its AdS_2 × S^2 near-horizon throat, and the charged-scalar instability threshold for a general form factor. For the explicit T-duality form factor the extremal branch terminates at r_ext = √2 l_0, where the extremal charge and the near-horizon electric field vanish while the AdS_2 radius remains finite at √3 l_0. At this endpoint the exact near-horizon instability parameter is negative. In the semiclassical regime the corresponding charge-to-mass threshold diverges as the endpoint is approached. Thus, for each fixed massive species with finite q/m, a sufficiently near-endpoint portion of the extremal branch is free of the local charged-scalar instability. For comparison, the Ayón-Beato-García (ABG) Einstein-nonlinear-electrodynamics solution has a nonvanishing extremal near-horizon electric field. For an additional minimally coupled charged-scalar probe, the corresponding local Schwinger threshold remains finite. Thus the divergent near-endpoint Schwinger barrier found in the T-duality branch is not a generic consequence of regularity.
ER -