Energy-momentum tensor is nonsymmetric for spin-polarized photons
  It has been assumed for a century that the energy-momentum tensor of the photon takes a symmetric form, with the renowned Poynting vector assigned as the same density for momentum and energy flow. Here we show that the symmetry of the photon energy-momentum tensor can actually be inferred from the known difference between the diffraction patterns of light with spin and orbital angular momentum, respectively. The conclusion is that the symmetric expression of energy-momentum tensor is denied, and the nonsymmetric canonical expression is favored. 
Xiang-Bai Chen and Xiang-Song Chen
physics.gen-ph physics.class-ph physics.optics