*Important notice: This news reports on an unedited version of an accepted paper and is awaiting final editing. Therefore, the paper should not be regarded as conclusive or treated as established information.
Researchers have analyzed the geometric and wave-optical properties of BTZ-like charged wormholes with disclinations to examine how these features influence photon paths and scalar wave propagation. Their findings were published in Scientific Reports.
Study: Geometric and wave optics analysis of BTZ-like charged wormholes with disclinations. Image Credit: vannet/Shutterstock.com
Disclinated Wormhole Optical Setting
Wormholes are theoretical structures that connect distant regions of spacetime and provide an interesting setting for studying general relativity. Many traversable wormhole models require exotic matter to remain stable, extending ideas first associated with the Einstein–Rosen bridge.
In lower-dimensional gravity, particularly in (2+1) dimensions, the Bañados–Teitelboim–Zanelli (BTZ) black hole provides an important theoretical framework for the development of related wormhole geometries. Topological defects, such as disclinations, further modify these geometries by producing conical structures that can affect the propagation of light and waves.
To investigate these effects, wave optics in curved spacetime is often studied using the scalar Helmholtz equation. The resulting behavior is also relevant to analog gravity systems and metamaterial designs, where similar geometric effects can be reproduced and examined experimentally.
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BTZCWH Spacetime Optical Analysis
The optical properties of the BTZ-like charged wormhole with disclinations were examined using both geometric and wave-optics approaches. Starting from the BTZCWH metric, which includes the disclination parameter (α), wormhole shape parameter (b0), and NS charge (Q), the Lagrangian formalism was used to obtain the conserved energy and angular momentum.
These quantities led to the impact parameter and the null-geodesic orbit equation, allowing the effects of α and Q on photon trajectories and finite-domain light bending to be determined. Circular photon orbits were also identified within the static region.
For wave optics, the scalar Helmholtz equation was transformed into a Schrödinger-type radial equation using proper distance. This produced a finite effective potential and, with self-adjoint Dirichlet conditions, a regular Sturm-Liouville problem with discrete real frequencies. The WKB analysis further connected the wave and geometric-optics results.
Photon Paths and Wave Behavior
The analysis provides several important insights into the optical behavior of charged BTZ wormholes containing disclinations. In the geometric-optics regime, the disclination parameter α has a strong influence on the bending of light.
As α decreases, the conical curvature becomes more pronounced, leading to greater deflection of photon trajectories. The finite-domain deflection integral shows that this topological contribution can become more significant than the gravitational contribution, particularly when α is considerably smaller than unity.
The NS charge Q also affects photon trajectories, with the calculated deflection increasing as Q increases. The study further identifies two types of circular null orbits: an unstable photon orbit located near the inner throat and a marginally stable circular orbit near the outer boundary of the static region. These features may be relevant when considering possible strong-lensing signatures.
The wave-optics analysis provides a complementary description. By transforming the scalar Helmholtz equation into a Schrödinger-type radial equation using proper distance, a finite effective potential was obtained at both boundaries of the static region.
Applying self-adjoint Dirichlet boundary conditions converted the problem into a regular Sturm-Liouville system, producing a discrete set of real frequencies and demonstrating the possibility of standing-wave modes within the wormhole cavity. The NS charge also modifies the geometry and curvature scale, thereby influencing wave propagation.
The radial WKB index connects the wave and ray descriptions. Geometric optics is recovered when ω2 is much greater than |R|, whereas low-frequency modes require a full wave-optical treatment.
Near the throat, diffraction, interference, and modal effects become especially important, showing why wave optics provides a more complete description in strongly curved, finite spacetime regions.
Optical Implications and Outlook
This study examined the geometric and wave-optical properties of static, traversable charged BTZ wormholes containing disclinations and a Neveu–Schwarz (NS) charge. The analysis was restricted to the finite static region of the wormhole, making the results particularly relevant to analog-gravity systems and possible metamaterial implementations rather than asymptotic spacetime behavior.
The disclination parameter α was found to strongly influence photon deflection, with its topological effects becoming more significant than gravitational contributions in certain parameter ranges. The study also confirmed the presence of circular null orbits, including an unstable photon ring near the wormhole throat.
From the wave-optics perspective, converting the Helmholtz equation into a Schrödinger-type form made it possible to obtain discrete standing-wave modes. These modes depend on both the NS charge and the orbital quantum number, showing how the wormhole geometry influences wave propagation.
The results further demonstrate that geometric optics can be recovered as the high-frequency limit of wave optics. At lower frequencies, however, wave effects such as diffraction and caustics become increasingly important, particularly near the throat. Overall, the findings improve understanding of light propagation in curved spacetime and provide a useful basis for future laboratory models of exotic gravitational geometries.
Journal Reference
Ahmed F., Bouzenada A., et al. (2026). Geometric and wave optics analysis of BTZ-like charged wormholes with disclinations. Scientific Reports. DOI: 10.1038/s41598-026-64171-x. https://www.nature.com/articles/s41598-026-64171-x.