Geodesic motion of photons in the space–time of a dynamic wormhole

The necessity of exotic matter violating the null energy condition is a basic problem of wormhole physics, at least in the case of static configurations in GR. However, some configurations of dynamic wormholes do not violate it. In this article, we study the motion of photons in the space--time of such a dynamic traversable wormhole filled with dust. We write down the geodesic equations for photons and solve them by considering the initial period of wormhole evolution.