Non-maximally Entangled State Of Quantum Teleportation And Secret Sharing

The carrier of information in quantum information science related to quantum state, so all the problems in this subject should be resolved by means of quantum theory. Therefore, quantum information science exhibits a number of advantages corresponding to classical counterpart. In the past twenty years, quantum information has made a surprise progress both in theoretical and experimental fields. It has created many miracles, such as absolute secure quantum key, quantum dense coding, quantum teleportation, and so on. Quantum communication is an important branch of quantum information science. It mostly involves quantum teleportation, quantum dense coding and quantum secret sharing et al. Up to now, there are a lot of articles, which include quantum teleportation and quantum secret sharing, have been published. But in most of the protocols, the channels are maximally entangled state, so these protocols are deterministic. In a realistic situation, however, decoherence and noise degrade the channel and we do not have a maximally entangled state anymore. This time applying the non- maximally entangled state as the quantum channel is more practical. But the price to pay is that the success probability is always less than unity.This paper mainly includes two aspects in the channel of non- maximally entangled state, which are quantum teleportation and quantum secret sharing.1. Quantum secret sharing of an arbitrary two particles entangled state via non-maximally entangled channelsA quantum secret sharing scheme is proposed for an arbitrary two particles entangled state among N agents. The scheme adopts non-maximally entangled Bell states as the quantum channels and generalized Bell states as the measurement basis. By introducing an auxiliary particle and making selective measurement on it, the receiver can obtain the original quantum state with a probability less than unit.2. Quantum teleportation of an arbitrary N-Qubit state via non-maximally entangled Bell stateA quantum teleportation scheme of an arbitrary N -qubit entangled state is proposed, by using non-maximally entangled Bell states as the quantum channels and generalized Bell states as the measurement basis. In order to reconstruct the original state, we should introduce an auxiliary particle and making selective measurement on it, the receiver can obtain the original quantum state with a probability less than unit.3. Controlled quantum teleportation of an arbitrary N-Qubit state via non-maximally entangled GHZ stateControlled quantum teleportation is the generalization of quantum teleportation. Only with the help of the controllers, the receiver can obtain the initial quantum state. A controlled quantum teleportation scheme of an arbitrary N -qubit entangled state is proposed, by using non-maximally entangled Greenberger-Horne-Zeilinger(GHZ) states as the quantum channels and generalized Bell states as the measurement basis. In order to obtain the initial quantum state, the measured of the receiver applying is the same as 2. So this protocol is also probabilistic.