Generation of entanglement between spin of an electron and polarization of a photon

This paper shows an electron and a photon, emitted in two consecutive steps from an atom following the absorption of a single photon, may be entangled in the presence of the spin-orbit interaction only. This entanglement strongly depends upon the polarization of the absorbed and of the radiated photons, kinematics of two emitted particles, and dynamics of photoionization; however, the photoemission dynamics plays no role in this entanglement. This hybrid entanglement can be used in teleporting a quantum state encoded in a flying/stationary material particle onto a light pulse, or vice versa. Such an electron-photon entanglement, in addition, will make it possible to learn about the polarization of a single photon or spin-polarization of a free electron without making any measurements on the corresponding particle itself.