A remark on an ansatz by M.W. Evans and the so-called   Einstein-Cartan-Evans unified field theory
  M.W.Evans tried to relate the electromagnetic field strength to the torsion of a Riemann-Cartan spacetime. We show that this ansatz is untenable for at least two reasons: (i) Geometry: Torsion is related to the (external) translation group and cannot be linked to an internal group, like the U(1) group of electrodynamics. (ii) Electrodynamics: The electromagnetic field strength as a 2-form carries 6 independent components, whereas Evans' electromagnetic construct F^\a is a vector-valued 2-form with 24 independent components. This doesn't match. One of these reasons is already enough to disprove the ansatz of Evans. 
Friedrich W. Hehl (Cologne and Missouri-Columbia)