-periodic light rays in conformally stationary spacetimes via Finsler geometry
arXiv:0803.0488
Abstract
In this paper we prove several multiplicity results of -periodic light rays in conformally stationary spacetimes using the Fermat metric and the extensions of the classical theorems of Gromoll-Meyer and Bangert-Hingston to Finsler manifolds. Moreover, we exhibit some stationary spacetimes with a finite number of -periodic light rays and compute a lower bound for the period of the light rays when the flag curvature of the Fermat metric is -pinched.
15 pages. Lemma 2.1 modified due to an incorrect statement