Weak deflection angle of black-bounce traversable wormholes using Gauss–Bonnet theorem in the dark matter medium

Abstract

In this paper, we first use the optical metrics of black-bounce traversable wormholes to calculate the Gaussian curvature. Then we use the Gauss–Bonnet theorem to obtain the weak deflection angle of light from the black-bounce traversable wormholes. We investigate the effect of dark matter medium on weak deflection angle using the Gauss– Bonnet theorem. We show how weak deflection angle of wormhole is affected by the bounce parameter a. Using the Gauss–Bonnet theorem for calculating weak deflection angle shows us that light bending can be thought as a global and topological effect.