Vacuum contribution of photons in the theory with Lorentz and   CPT-violating terms
  The photon contribution to the divergences and conformal anomaly in the theory with Lorentz and CPT-violating terms is evaluated. We calculate one-loop counterterms coming from the integration over electromagnetic field and check that they possess local conformal invariance. Furthermore, conformal anomaly and anomaly-induced effective action are calculated. It turns out that the new terms do not affect the dynamics of conformal factor in the anomaly-driven inflation (Starobinsky model) and its extensions. At the same time, one can expect these terms to affect gravitational wave equation and, in general, cosmic perturbations. 
Tiberio de Paula Netto and Ilya L. Shapiro
hep-th