Quantum entanglement of electromagnetic field in non-inertial reference frames

Recently relativistic quantum information has received considerable attention due to its theoretical importance and practical application. In particular, quantum entanglement in non-inertial reference frames has been studied for scalar and Dirac fields. As a further step along this line, we here shall investigate quantum entanglement of electromagnetic field in non- inertial reference frames. In particular, the entanglement of the photon helicity entangled state is extensively analysed. Interestingly, the resultant logarithmic negativity and mutual information remain the same as those for inertial reference frames, which is completely different from that previously obtained for the particle number entangled state.