Dressing a naked singularity with zero-point length
Abstract
We regularize the central density cusp of the Joshi--Malafarina--Narayan spacetime using a normalized kernel motivated by a zero-point length. For an unbounded cusp, the convolution and enclosed mass are obtained analytically; truncating this density gives a regular, horizonless tangential-pressure interior matched to Schwarzschild. Convolving the finite cloud instead preserves its total mass and yields a smooth matter tail. A compactness bound establishes horizon avoidance for this second prescription. We determine the central lapse, establish causal geodesic completeness despite extreme optical delays, derive a uniform optical-delay formula across the critical compactness, and identify the stable interior light ring of ultracompact configurations. The massless scalar probe operator is nonnegative, while semiclassical trapped modes exhibit strongly suppressed leakage. An explicit pressure-closure comparison separates robust geometric properties from closure-dependent delay exponents. Planck-scale examples illustrate extreme redshifts and delays, but their photon interpretation requires physics beyond classical propagation in the core. The construction specifies an effective static source, rather than a microscopic matter theory or a dynamical resolution of collapse.
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BibTeX
@misc{jusufi2026dressing,
title = {{Dressing a naked singularity with zero-point length}},
author = {Kimet Jusufi and Francisco S. N. Lobo},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.24000},
eprint = {2610.24000},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.24000},
}
RIS
TY - UNPB
TI - Dressing a naked singularity with zero-point length
AU - Kimet Jusufi
AU - Francisco S. N. Lobo
PY - 2026
DA - 2026/10/15
PB - arXiv
DO - 10.48550/arxiv.2610.24000
UR - https://arxiv.org/abs/2610.24000
AB - We regularize the central density cusp of the Joshi--Malafarina--Narayan spacetime using a normalized kernel motivated by a zero-point length. For an unbounded cusp, the convolution and enclosed mass are obtained analytically; truncating this density gives a regular, horizonless tangential-pressure interior matched to Schwarzschild. Convolving the finite cloud instead preserves its total mass and yields a smooth matter tail. A compactness bound establishes horizon avoidance for this second prescription. We determine the central lapse, establish causal geodesic completeness despite extreme optical delays, derive a uniform optical-delay formula across the critical compactness, and identify the stable interior light ring of ultracompact configurations. The massless scalar probe operator is nonnegative, while semiclassical trapped modes exhibit strongly suppressed leakage. An explicit pressure-closure comparison separates robust geometric properties from closure-dependent delay exponents. Planck-scale examples illustrate extreme redshifts and delays, but their photon interpretation requires physics beyond classical propagation in the core. The construction specifies an effective static source, rather than a microscopic matter theory or a dynamical resolution of collapse.
ER -