THE PROPAGATION OF LIGHT IN CAUSAL SET THEORY

This is a report based on a student research project con- ducted at San Jose State University in the Spring of 2009, which was a continuation of a similar project conducted in the Spring 2008. The goal of both projects was to investigate the possibility that the speed of a photon depends on its energy and thus that the speed of light is not an absolute constant. Both projects were motivated and inspired by the launch of the FERMI Gamma Ray Space Telescope in June 2008, which detects high energy photons coming from Gamma ray bursts. The investigation was done in the context of causal sets implemented in MATLAB. The probability amplitudes were computed using a variant of the Feynman path integral approach. Our work indicates that there is a relationship between a photon's energy and the standard deviation of its velocity.