Quasinormal modes, complex null geodesics and singularity resolution in regular AdS black holes
Abstract
The black hole singularity is hidden behind its horizon, and it is difficult to determine whether it is resolved by quantum gravity or stringy effects. For an AdS-Schwarzschild black hole, it is known that the two-point function of the dual conformal field theory has a singularity associated with a null geodesic that bounces off the black hole singularity. In this paper, we investigate how the resolution of the black hole singularity is encoded in the dual conformal field theory by considering regular AdS black holes as regularized geometries. Using WKB analysis, we compute the quasinormal modes of regular AdS black holes and read off the dual two-point functions from the modes. We find that the singularity corresponding to the bouncing null geodesic for singular black holes is replaced by a smooth bump associated with a complex, rather than real, null geodesic. The location of the complex geodesic singularity is supported by analyzing the structure of the operator product expansion for the two-point function. Our results provide a holographic signature of black hole singularity resolution and clarify how information about the regular interior is encoded in boundary correlation functions.
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BibTeX
@misc{chen2026quasinormal,
title = {{Quasinormal modes, complex null geodesics and singularity resolution in regular AdS black holes}},
author = {Heng-Yu Chen and Yasuaki Hikida and Yasutaka Koga},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.30915},
eprint = {2610.30915},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.30915},
}
RIS
TY - UNPB
TI - Quasinormal modes, complex null geodesics and singularity resolution in regular AdS black holes
AU - Heng-Yu Chen
AU - Yasuaki Hikida
AU - Yasutaka Koga
PY - 2026
DA - 2026/10/22
PB - arXiv
DO - 10.48550/arxiv.2610.30915
UR - https://arxiv.org/abs/2610.30915
AB - The black hole singularity is hidden behind its horizon, and it is difficult to determine whether it is resolved by quantum gravity or stringy effects. For an AdS-Schwarzschild black hole, it is known that the two-point function of the dual conformal field theory has a singularity associated with a null geodesic that bounces off the black hole singularity. In this paper, we investigate how the resolution of the black hole singularity is encoded in the dual conformal field theory by considering regular AdS black holes as regularized geometries. Using WKB analysis, we compute the quasinormal modes of regular AdS black holes and read off the dual two-point functions from the modes. We find that the singularity corresponding to the bouncing null geodesic for singular black holes is replaced by a smooth bump associated with a complex, rather than real, null geodesic. The location of the complex geodesic singularity is supported by analyzing the structure of the operator product expansion for the two-point function. Our results provide a holographic signature of black hole singularity resolution and clarify how information about the regular interior is encoded in boundary correlation functions.
ER -