Motion of a Vector Particle in a Curved Space-time. IV. Asymptotical shape of caustic

TL;DR

This paper investigates how the spin of a photon influences its trajectory in Schwarzschild spacetime, deriving the explicit shape of the resulting caustic formed by light rays affected by spin-gravity interaction.

Contribution

It provides an explicit form of the caustic shape caused by spin effects on photon motion in curved spacetime, extending previous first-order correction analyses.

Findings

Light rays form a caustic due to spin-gravity interaction.

Explicit mathematical form of the caustic shape is derived.

Spin influences photon trajectories in Schwarzschild spacetime.

Abstract

The studies of influence of spin on a photon motion in a Schwartzschild spacetime is continued. In the previous paper [2] the first order correction to the geodesic motion is reduced to a non-uniform linear ordinary differential equation and the equation obtained has been solved by the standard method of integration of the Green function. If each photon draws a world line specified by this solution then light rays from infinitely distant source form a caustic which does not appear without the spin-gravity interaction. The goal of the present work is to obtain explicit form of caustic.