Symmetry entanglement in polarization biphoton optics

We study kinematic and dynamic ways of forming entangled states of quantum light fields due to their local and global polarization SU (2) symmetries. The kinematic entanglement is shown to be associated with particular polarization bases in the spaces of quantum states of multi-mode radiation, which are generated by the global SU (2) — symmetry. Dynamic entanglement is due to SU (2) symmetries of the Hamiltonians of the matter-radiation interaction. We also define some entanglement measures, which are related to characteristics of light depolarization. Applications of results obtained in biphoton optics are briefly discussed.