Unification of Gravity and Electromagnetism II A Geometric Theory
  It is shown that unification of gravity and electromagnetism can be achieved using an affine non-symmetric connection $\Gamma^\lambda_{\mu\nu} \neq \Gamma^\lambda_{\nu\mu}$ and $\Gamma_\mu = \Gamma^\lambda_{[\mu\lambda]}\neq 0$. $\Gamma_\mu$ is shown to be the source of the electromagnetic field. This unification is based on {\em projective invariance} which is broken by matter fields, opening up the possibility of a unified theory of all forces in which gravity emerges as a classical field. 
Partha Ghose
gr-qc