A Coding and Automatic Error-Correction Circuit Based on the Five-Particle Entangled State

In this paper, we discuss the concepts of quantum coding and error correction for a five-particle entangled state. Error correction can correct bit-reverse or phase-flip errors of one and two quantum states and is no longer limited to only one quantum state. We encode a single quantum state into a five-particle entangled state before being transferred to the sender. We designed an automatic error-correction circuit to correct errors caused by noise. We also simplify the design process for a multiple quantum error-correction circuit. We compare error-correction schemes for five and three entangled particles in terms of efficiency and capabilities. The results show that error-correction efficiency and fidelity are im- proved.

A quantum secure direct communication protocol based on a five-particle cluster state and classical XOR operation

In order to transmit secure messages,a quantum secure direct communication protocol based on a five-particle cluster state and classical XOR operation is presented.The five-particle cluster state is used to detect eavesdroppers,and the classical XOR operation serving as a one-time-pad is used to ensure the security of the protocol.In the security analysis,the entropy theory method is introduced,and three detection strategies are compared quantitatively by using the constraint between the information that the eavesdroppers can obtain and the interference introduced.If the eavesdroppers intend to obtain all the information,the detection rate of the original ping-pong protocol is 50%;the second protocol,using two particles of the Einstein-Podolsky-Rosen pair as detection particles,is also 50%;while the presented protocol is 89%.Finally,the security of the proposed protocol is discussed,and the analysis results indicate that the protocol in this paper is more secure than the other two.

Quantum Private Comparison of Equality Based on Five-Particle Cluster State

A protocol for quantum private comparison of equality(QPCE) is proposed based on five-particle cluster state with the help of a semi-honest third party(TP). In our protocol, TP is allowed to misbehave on its own but can not conspire with either of two parties. Compared with most two-user QPCE protocols, our protocol not only can compare two groups of private information(each group has two users) in one execution, but also compare just two private information. Compared with the multi-user QPCE protocol proposed, our protocol is safer with more reasonable assumptions of TP. The qubit efficiency is computed and analyzed. Our protocol can also be generalized to the case of 2N participants with one TP. The 2N-participant protocol can compare two groups(each group has N private information)in one execution or just N private information.