Distinguishing rotating naked singularities from Kerr-like wormholes by their deflection angles of massive particles

TL;DR

This paper investigates how relativistic massive particles are deflected by rotating naked singularities and Kerr-like wormholes, revealing differences that could help observationally distinguish these exotic spacetimes.

Contribution

It extends previous work by analyzing the deflection of massive particles in JNW and Kerr-like wormhole spacetimes using optical metrics and Hamilton-Jacobi methods.

Findings

Deflection angle depends on parameters $\

Kerr-like wormholes cause stronger deflections than JNW spacetimes.

The methods recover known light deflection results and highlight potential observational differences.

Abstract

We study the gravitational deflection of relativistic massive particles by Janis-Newman-Winicour (JNW) spacetimes (also known as a rotating source with a surface-like naked singularity), and a rotating Kerr-like wormholes. Based on the recent article [K. Jusufi, Phys. Rev. D 98, 064017 (2018)], we extend some of these results by exploring the effects of naked singularity and Kerr-like objects on the deflection of particles. We start by introducing coordinate transformation leading to an isotropic line element which gives the refraction index of light for the corresponding optical medias. On the other hand, the refraction index for massive particles is found by considering those particles as a de Broglie wave packets. To this end, we apply the Gauss-Bonnet theorem to the isotropic optical metrics to find the deflection angles. Our analysis shows that, in the case of the JNW spacetime the deflection angle is affected by the parameter $0<\gamma<1$, similarly, we find that the deformation parameter $\lambda$ affects the deflection angle in the case of Kerr-like wormholes. In addition to that, we presented a detailed analysis of the deflection angle by means of the Hamilton-Jacobi equation that lead to the same results. As a special case of our results the deflection angle of light is recovered. Finally, we point out that the deflection of particles by Kerr-like wormholes is stronger compared to JNW spacetime, in particular this difference can be used to shed some light from observational point of view in order to distinguish the two spacetimes.