Photon gravitational defection in Lorentz violating scenarios
  The effect of Lorentz symmetry violation in the phenomenon of photon gravitational bending, is investigated. Using a semiclassical approach, where the photon is described by the Carrol-Field-Jackiw (CFJ) electrodynamics which is responsible for implementing the Lorentz symmetry violation, the gravitational deflection angle related to the CFJ photon is computed. As expected, this bending angle experiences a deviation from the usual Einstein result and the latter is recovered in the appropriate limit. A comparison between the theoretical prediction and the experimental results allows to conclude that no trace of Lorentz symmetry breaking is found provided the components of the background vector field are $\lesssim 10^{-8}$ eV. 
Antonio Accioly, Gustavo P. de Brito and Jos\'e Helay\"el-Neto
physics.gen-ph hep-th