Research On Entanglement Concentration And Logic Quantum Gate Based On C-GHZ State

One of the most important discoveries of physics is Quantum mechanics in the 20 th century.It forms the main basic theory of modern physics together with the theory of relativity.Quantum mechanics has achieved rapid development in the tireless efforts of research workers.Till now,The research on the field of quantum information using the basic principles of quantum mechanics have made encouraging progress.And many of the research results have been verified under experimental conditions.Now,the related research of quantum information mainly includes two fields of quantum computing and quantum communication.Among them,the classical schemes of quantum communication include quantum teleportation,quantum security direct communication,quantum key distribution,quantum secret sharing and so on.And quantum computation includes quantum algorithm and related hardware devices,such as Shor's algorithm and Grover's algorithm,and all kinds of quantum logic gates.However,both quantum communication and quantum computing will inevitably be disturbed by the external environment,so that the quantum state of the system is decohered.In order to solve this problem caused by noise in quantum communication,The protocols about Quantum state logic coding,Quantum entanglement purification and concentration have been proposed.Among them,the Quantum state logic coding is mainly used to correct the errors of quantum states.The Protocol of entanglement purification is to solve the situation that the quantum state is severely degenerate into a mixed state,and the Protocol of entanglement concentration is to solve the situation that the quantum state decoherence is the non-maximum entangled state.Therefore,in order to enhance the anti-interference ability of the scheme,logical coding has become a good alternative.One of the ways to design a quantum communication scheme is based on the Greenberger-Horne-Zeilinger(C-GHZ)states.The C-GHZ state is a kind of logical qubit entangled state composed of many physical qubits.This kind of entangled state has a strong anti-interference ability compared with the ordinary quantum states,and this ability has been verified in experiments.Our research is also based on this kind of quantum state.The first research point of this paper is the entanglement concentration scheme based on C-GHZ states of theelectronic system.In order to achieve entanglement concentration of the C-GHZ state of the electronic system,we first constructed a P-gate using a charge detector.Then we will show our entanglement concentration protocol by using the P-gate and gradually extended to the protocol to any C-GHZ state.At last,we will continue to improve the probability of entanglement concentration success through the second use of the concentration results.On the other hand,due to C-GHZ has good resistance to photon loss,So it has great application prospect in quantum fault-tolerant computation and distributed network.The latest research shows that it has a new encoding scheme which designed by C-GHZ states can effectively prevent the problem of photon loss.Therefore,we design some quantum logic gate to this kind of encoding schema.Including single logic qubit phase flip gate and logic qubit flip gate,and the two logic qubit control-not gate.We can effectively perform logic qubit operations on quantum circuits by using these logic gates.