Quantum Crossing Symmetry as Heart of Ghost Imaging
  In this paper it is shown that the key to understanding the ghost imaging mystery are the crossing symmetric photon reactions in the nonlinear media. Then, an intuitive mechanism for the description of the ghost imaging in terms of the quantum mirror (QM) is presented. Moreover, we prove that the ghost imaging laws depend only on the energy-momentum conservation and not on the photons entanglement. 
D. B. Ion (1), M.L. Ion (2) and L. Rusu (1)