Error correction of polarization entanglement in hyper-entangled state

We present two schemes for error-correction of polarization entanglement with time-bin entanglement and frequency entanglement in hyper-entangled state. In these two protocols, by performing the polarization parity-check operation, the bit-flip and phase-flip errors on the polarization part can be corrected and eliminated in one step. The parties in quantum communication can obtain maximally hyper-entangled states in two degrees of freedom in a deterministic way. Our protocols for purification are useful in practical applications for long-distance quantum communication. (paper)