Abstract:

We gave the spin states of twophoton using quantum theory approach, i.e., twophoton spin eigen states were expressed by the superposition of the direct product of two single photon spin states. Then, we obtained the quantum representation of twophoton entanglement states, which are different from the classical polarization vector expression of twophoton entanglement state. The results could be used in quantum communication and quantum computation.

Key words: twophoton, spin state, entanglement state