Optical constraints on rotating logarithmic- and exponential-entropy wormholes from strong-field lensing
Abstract
The longstanding issue of whether horizonless compact objects can mimic black holes at horizon scales is addressed, a problem that persists because the shadow diameter alone is degenerate across a wide class of geometries. For slowly rotating traversable wormholes, we precisely formulate the optical appearance as a set of observables derived from equatorial null geodesics, yielding necessary and sufficient conditions for a multi-parameter fingerprint. Using a new lapse function that interpolates between exponential and rational redshift profiles, we obtain the photon-sphere condition, the strong-deflection lensing coefficients, and the Lyapunov exponent in closed form. The equations yield two families of wormhole solutions dependent on logarithmic and exponential entropy parameters. We compare the resulting quantum-modified spacetimes with Kerr and four regular black holes. The shadow diameter is shown to be tunable to within 5% to 11% of Kerr for all models considered, so that |RshWH/RshKerr−1| ≲ 0.11 and the shadow alone cannot separate the models. The degeneracy is lifted when the rotational asymmetry, lensing coefficients, Lyapunov exponent, and orbital frequency are combined: for the $5$-component fingerprint F=(Arot,abar,bbar, Lya,Oph), the fractional deviation Δi=(FiWH−FiKerr)/ FiKerr satisfies |Δi|≳ 0.05 for every component, with the largest departures in the second lensing coefficient and the Lyapunov exponent. The combined discrimination signal reaches a signal-to-noise ratio of about $3.8$ to $3.9$ against Kerr and about $3.7$ against the Kazakov--Solodukhin benchmark, which is sufficient to break the shadow-diameter degeneracy at the 10% measurement level.
Related
- Slowly Rotating Wormholes in f(R,T) Gravity: Particle Dynamics and Weak-field Lensing
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- Rotating Barrow entropy-inspired wormholes versus black holes: null trajectories, shadow morphology, and exotic matter
- Thin-shell wormholes from magnetic black holes in exponential electrodynamics
- Logarithmic corrections to the entropy of near-extremal rotating black holes
BibTeX
@misc{yergaliyeva2026optical,
title = {{Optical constraints on rotating logarithmic- and exponential-entropy wormholes from strong-field lensing}},
author = {A. Errehymy G. Yergaliyeva and S. K. Maurya and B. Turimov and I. Ibragimov and J. Rayimbaev},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.25132},
eprint = {2610.25132},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.25132},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Optical constraints on rotating logarithmic- and exponential-entropy wormholes from strong-field lensing
AU - A. Errehymy G. Yergaliyeva
AU - S. K. Maurya
AU - B. Turimov
AU - I. Ibragimov
AU - J. Rayimbaev
PY - 2026
DA - 2026/10/18
PB - arXiv
DO - 10.48550/arxiv.2610.25132
UR - https://arxiv.org/abs/2610.25132
AB - The longstanding issue of whether horizonless compact objects can mimic black holes at horizon scales is addressed, a problem that persists because the shadow diameter alone is degenerate across a wide class of geometries. For slowly rotating traversable wormholes, we precisely formulate the optical appearance as a set of observables derived from equatorial null geodesics, yielding necessary and sufficient conditions for a multi-parameter fingerprint. Using a new lapse function that interpolates between exponential and rational redshift profiles, we obtain the photon-sphere condition, the strong-deflection lensing coefficients, and the Lyapunov exponent in closed form. The equations yield two families of wormhole solutions dependent on logarithmic and exponential entropy parameters. We compare the resulting quantum-modified spacetimes with Kerr and four regular black holes. The shadow diameter is shown to be tunable to within 5% to 11% of Kerr for all models considered, so that |R_sh^WH/R_sh^Kerr−1| ≲ 0.11 and the shadow alone cannot separate the models. The degeneracy is lifted when the rotational asymmetry, lensing coefficients, Lyapunov exponent, and orbital frequency are combined: for the $5$-component fingerprint F=(Arot,abar,bbar, Lya,Oph), the fractional deviation Δ_i=(F_i^WH−F_i^Kerr)/ F_i^Kerr satisfies |Δ_i|≳ 0.05 for every component, with the largest departures in the second lensing coefficient and the Lyapunov exponent. The combined discrimination signal reaches a signal-to-noise ratio of about $3.8$ to $3.9$ against Kerr and about $3.7$ against the Kazakov--Solodukhin benchmark, which is sufficient to break the shadow-diameter degeneracy at the 10% measurement level.
ER -