Planck-scale black hole remnants inside neutron stars
Abstract
We examine a Planck-scale regular black-hole remnant in neutron-star matter using a T-duality-inspired effective geometry and explicitly separate geometrical results from assumptions about absorption and emission. Within the static family, the surface-gravity temperature grows as (M−Mext)1/2 after a small mass increase. A constant-greybody Stefan--Boltzmann approximation gives a Hawking power proportional to (M−Mext)2 and can produce a stable lower balance point and an unstable growth threshold under stated hypotheses. For l0=ℓPl, however, the formal lower equilibrium has an excess mass of only 10−45--10−46 kg for order-unity absorption efficiency, so the canonical description is inconsistent with individual neutron captures. For a fiducial area-scale absorption cross section with unit coefficient, the mean capture interval is 5.4×108 yr and the initial nonradiating growth timescale is 9.1×1027 yr. Under this assumption, a Planck-mass remnant inside a neutron star is therefore effectively inert and, without additional feeding, cannot destroy the star within the age of the Universe. A stationary capture--relaxation state additionally requires an effective microscopic emission law; it is not established by zero temperature alone. Hydrodynamic accretion requires control of wave effects and a mean-free-path criterion; its onset corresponds to masses of order 1011--1012 kg for representative matter parameters. Direct zero-point-length corrections there are negligible, of order 10−40 at a femtometre. We discuss conditional growth thresholds, critical slowing near an unstable balance, dark-matter feeding, angular-momentum transfer, and the requirements for neutron-star survival constraints.
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BibTeX
@misc{jusufi2026planckscale,
title = {{Planck-scale black hole remnants inside neutron stars}},
author = {Kimet Jusufi and Francisco S. N. Lobo},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.10589},
eprint = {2610.10589},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.10589},
}
RIS
TY - UNPB
TI - Planck-scale black hole remnants inside neutron stars
AU - Kimet Jusufi
AU - Francisco S. N. Lobo
PY - 2026
DA - 2026/10/06
PB - arXiv
DO - 10.48550/arxiv.2610.10589
UR - https://arxiv.org/abs/2610.10589
AB - We examine a Planck-scale regular black-hole remnant in neutron-star matter using a T-duality-inspired effective geometry and explicitly separate geometrical results from assumptions about absorption and emission. Within the static family, the surface-gravity temperature grows as (M−M_ext)^1/2 after a small mass increase. A constant-greybody Stefan--Boltzmann approximation gives a Hawking power proportional to (M−M_ext)^2 and can produce a stable lower balance point and an unstable growth threshold under stated hypotheses. For l_0=ℓ_Pl, however, the formal lower equilibrium has an excess mass of only 10^−45--10^−46 kg for order-unity absorption efficiency, so the canonical description is inconsistent with individual neutron captures. For a fiducial area-scale absorption cross section with unit coefficient, the mean capture interval is 5.4×10^8 yr and the initial nonradiating growth timescale is 9.1×10^27 yr. Under this assumption, a Planck-mass remnant inside a neutron star is therefore effectively inert and, without additional feeding, cannot destroy the star within the age of the Universe. A stationary capture--relaxation state additionally requires an effective microscopic emission law; it is not established by zero temperature alone. Hydrodynamic accretion requires control of wave effects and a mean-free-path criterion; its onset corresponds to masses of order 10^11--10^12 kg for representative matter parameters. Direct zero-point-length corrections there are negligible, of order 10^−40 at a femtometre. We discuss conditional growth thresholds, critical slowing near an unstable balance, dark-matter feeding, angular-momentum transfer, and the requirements for neutron-star survival constraints.
ER -