A Lorentz Violating Theory: Its Nonminimal Extension in the Photon   Sector
  The relentless efforts of the physics community has not yet availed us the solution of how to unify the Quantum Mechanics with General Relativity, a puzzle that has engaged the minds of the physicists for almost a century. The insufficiency of today's and foreseeable future's technology for a direct reach into the Planck energies at which the fundamental theory, the Quantum Theory of Gravity, lies has lead to the search of the low energy effects of that fundamental Planck level theory irregardless of the details of it. In this thesis, one of the leading candidates of such an exotic effect, that is the violation of Lorentz and CPT symmetries is analyzed. The action level effective field theoretical framework for such an analysis called Standard Model Extension has already been in the literature for the last two decades; here, the nonminimal photon sector of such a framework is examined from a quantum field theoretical point of view. All possible polarization vectors for different kinds of CPT violations, the generic forms of the dispersion relations that these polarization vectors satisfy, and the corresponding propagators of the photon field are explicitly calculated. Special models of Lorentz violations are introduced, and a particular one called vacuum orthogonal model is analyzed extensively. It is found that this particular form of Lorentz violation cannot induce any effects that is detectable in the vacuum propagation of the photon. Isotropic and leading order cases of the Lorentz violation is studied and this found result is explicitly shown. 
Soner Albayrak
hep-ph hep-th