- Accepted Paper
Self-force on a static scalar charge in traversable wormholes
Phys. Rev. D - Accepted 28 October, 2026
DOI: https://doi.org/10.1103/6qk8-9mhc
Phys. Rev. D - Accepted 28 October, 2026
DOI: https://doi.org/10.1103/6qk8-9mhc
The self-force acting on a charged particle is sensitive to the global structure of curved spacetime and can serve as a probe of geometry beyond local curvature. We compute the static scalar self-force on a point charge in the two-parameter family of spherically symmetric wormholes introduced by Konoplya and Zhidenko, members of the broader Morris–Thorne class of traversable wormholes. Using mode-sum regularization, we analyze its dependence on the shape exponent , which controls the throat geometry, and the redshift parameter , which determines the redshift function and tidal strength. We find that the self-force is generally not unidirectional: it can change sign with radial distance from the throat, with up to two distinct zero crossings depending on . This sign-switching behavior can be attributed to the competition between the wormhole’s short-range tidal gradients and the long-range effect of its topological flaring out. In the ultrastatic case where tidal forces vanish, the self-force remains strictly unidirectional. Furthermore, we provide a systematic characterization of how both the direction and large-distance falloff depend on the wormhole parameters. For sufficiently large , the force can decay at a slower rate than the canonical behavior typical of isolated-body spacetimes, with stronger flaring (more negative ) leading to more rapid decay. In the combined limit and , the asymptotic falloff approaches that of the static scalar self-force in the Ellis wormhole.
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