Figure 1
Scheme of two-copy teleportation protocol based on Bell measurements. Alice and Bob share two copies of entangled resource χ, with particles 1 and 3 in Alice’s side, and particles 2 and 4 in Bob’s side. Alice wants to transmit the unknown state ρin of particle 0 to Bob with optimal fidelity. The two-copy teleportation protocol based on Bell measurements is as follows: firstly, Alice (resp. Bob) performs a joint local unitary operation W (resp. V) on particles 1 (resp. 2) and particle 3 (resp. 4) to correlate these two particles. Then Alice makes joint Bell measurement on particles 0 and 1 and informs Bob the measurement results by classical communication. According to the measurement results, Bob chooses corresponding unitary transformations {T} on his particles 2 and 4 to restore the input state ρin on particle 2.
