5p-Q-9 Purification of multi-particle entangled states

Mio Murao, Martin Bodo Plenio, Sandu Popescu +2 more

Mio Murao, Martin Bodo Plenio, Sandu Popescu +2 more

Ye Liu, Chunmei Yao, Guang‐Can Guo

We present two purification schemes for nonmaximally entangled states. We first show that two parties, Alice and Bob, start with shared less-entangled three-particle states to probabilistically produce a three-particle Greenberger–Horne–Zeilinger state by Bell state measurements and positve operator valued measure (POVM) or a unitary transformation. Then, by a straightforward generalization of the schemes, the purification of a multi-particle entangled state can be realized.

Mio Murao, Martin Bodo Plenio, Sandu Popescu +2 more

Purification schemes for multiparticle entangled states cannot be treated as straightforward extensions of those two-particle ones because of the lack of symmetry they possess. We propose purification protocols for a wide range of mixed entangled states of many particles. These are useful for understanding entanglement, and could be of practical significance in multiuser cryptographic schemes or distributed quantum computation and communication. We show that operating locally on multiparticle entangled states directly is more efficient than relying on two-particle purification.

Dirk Bouwmeester, Jian-Wei Pan, Matthew Daniell +2 more

Gong Ren-shan

The author investigate the purification of entangled two-particle states and entangled three-particle states by entanglement swapping,then populanze it to entangled multi-particle states,and the author find that the totol probability is 2|b|~2 in all kinds of states.In the process,only the unitary transformation and Hadamard transformation are nsed.