Draining Without Emptying a Stringy Black Hole: Repetitive Electric Penrose Process
Abstract
This paper studies the repetitive electric Penrose process in the Gibbons-Maeda-Garfinkle-Horowitz-Strominger (GMGHS) black hole under the optimal condition for maximum energy extraction. Unlike the Reissner-Nordström (RN) black hole, the effective potential curve of the incident particle in the GMGHS black hole remains unchanged during the iterations. The iteration termination conditions are determined by two aspects: the escape condition requires that particle 0 can overcome the effective potential peak and escape to infinity, and this condition is independent of the black hole charge; the existence condition for negative-energy particle 1 requires the black hole charge to be sufficiently large, indicating that the repetitive process cannot completely consume the charge of the GMGHS black hole to zero. Numerical simulations show that the return on investment of energy extraction can exceed 100%, but the energy utilization efficiency does not exceed 50%, and most of the extractable energy is converted into an increase in the irreducible mass of the black hole. In addition, a smaller decay radius and a larger absolute value of the charge-to-mass ratio of particle 1 can improve the return on investment and energy utilization efficiency of energy extraction; the larger the specific energy of the incident particle, the smaller the return on investment of energy extraction, while the energy utilization efficiency remains unchanged; for an initially non-extremal black hole, as the initial charge increases, the return on investment of energy extraction increases monotonically, while the energy utilization efficiency first increases and then decreases. After the iterations end, the black hole still retains extractable energy, and neither the charge nor the mass vanishes.
Related
- Electric Penrose process in spherically symmetric regular black holes with and without a cosmological constant
- A large size of the pion-like excitations in the stringy fluid above Tch is model independent and required by current algebra
- The Stringy Origin of Kerr Multipoles
- Stringy resolution of bouncing singularities
- The Stringy Photon Sphere
BibTeX
@misc{li2026draining,
title = {{Draining Without Emptying a Stringy Black Hole: Repetitive Electric Penrose Process}},
author = {Huai-Fan Li and Xiong-Ying Guo and Ke Wang and Hong Lei},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.37713},
eprint = {2610.37713},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.37713},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Draining Without Emptying a Stringy Black Hole: Repetitive Electric Penrose Process
AU - Huai-Fan Li
AU - Xiong-Ying Guo
AU - Ke Wang
AU - Hong Lei
PY - 2026
DA - 2026/10/27
PB - arXiv
DO - 10.48550/arxiv.2610.37713
UR - https://arxiv.org/abs/2610.37713
AB - This paper studies the repetitive electric Penrose process in the Gibbons-Maeda-Garfinkle-Horowitz-Strominger (GMGHS) black hole under the optimal condition for maximum energy extraction. Unlike the Reissner-Nordström (RN) black hole, the effective potential curve of the incident particle in the GMGHS black hole remains unchanged during the iterations. The iteration termination conditions are determined by two aspects: the escape condition requires that particle 0 can overcome the effective potential peak and escape to infinity, and this condition is independent of the black hole charge; the existence condition for negative-energy particle 1 requires the black hole charge to be sufficiently large, indicating that the repetitive process cannot completely consume the charge of the GMGHS black hole to zero. Numerical simulations show that the return on investment of energy extraction can exceed 100%, but the energy utilization efficiency does not exceed 50%, and most of the extractable energy is converted into an increase in the irreducible mass of the black hole. In addition, a smaller decay radius and a larger absolute value of the charge-to-mass ratio of particle 1 can improve the return on investment and energy utilization efficiency of energy extraction; the larger the specific energy of the incident particle, the smaller the return on investment of energy extraction, while the energy utilization efficiency remains unchanged; for an initially non-extremal black hole, as the initial charge increases, the return on investment of energy extraction increases monotonically, while the energy utilization efficiency first increases and then decreases. After the iterations end, the black hole still retains extractable energy, and neither the charge nor the mass vanishes.
ER -