Massless DKP field in Lyra manifold
  Massless scalar and vector fields are coupled to Lyra geometry by means of Duffin-Kemmer-Petiau (DKP) theory. Using Schwinger Variational Principle, equations of motion, conservation laws and gauge symmetry are implemented. We find that the scalar field couples to the anholonomic part of the torsion tensor, and the gauge symmetry of the electromagnetic field is not breaking by the coupling with torsion. 
R. Casana, C. A. M. de Melo and B. M. Pimentel