| Today's society is in an era of great information transformation,and the information processing technology and transmission methods are undergoing earth-shaking changes.At the same time,a variety of issues have emerged in an endless stream,among which the security and efficiency issues of information transmission are particularly important.Due to the unique nature of quantum itself,the emerging quantum information processing technology has natural advantages in solving these problems,so it has attracted more and more attention and investment.Quantum entanglement is one of the core resources of quantum information processing technology.Due to the complexity of the entanglement of the multi-body quantum system and the decoherence of coupling with the environment,the research of quantum entanglement has always been a hot issue of quantum information,and it is of vital importance to the development of quantum communication.Based on the basic idea of quantum teleportation,this paper uses the method of combining quantum channel and classical channel,through the construction of quantum entanglement channel and quantum local unitary operation,have theoretically realized the remote quantum cloning of multi-body quantum entangled state 1?N,and have focused on the remote quantum cloning scheme,and have calculated the fidelity and entanglement of the cloned output.The research results are as follows:1.First,the remote quantum cloning of the four-body quantum entangled state 1?3 is studied.Two appropriate schemes are selected to clone different forms of input states.By constructing a suitable quantum channel,it is found that the remote quantum cloning scheme in this paper is a universal scheme.The fidelity of the input state and output state is 2/3,and the entanglement of the output state is-[(2/3|?|2+1/3|?|2)log2(2/3|?|2+1/3|?|2)+(1/3|?|2+2/3|?|2)log2(1/3|?|2+2/3|?|2)].2.The four-body quantum entangled state 1?4 remote quantum cloning is studied,including the design of the remote quantum cloning scheme,and the establishment of the quantum channel under this scheme,and the fidelity and entanglement of the cloned output state are calculated.The fidelity of the output result of the four-body quantum entangled state 1?4 remote quantum clone does not change with the unknown coefficient of the input state.The fidelity of its input state and output state is calculated to be a constant 2/3.And the entanglement of the output state is-[(2/3|?|2+1/3|?|2)log2(2/3|?|2+1/3|?|2)+(1/3|?|2+2/3|?|2)log2(1/3|?|2+2/3|?|2)].3.This paper have attempted to generalize the four-body quantum entangled state 1?5 remote quantum cloning.As the number of receivers increases,the cloning scheme becomes complicated and the quantum channel design becomes more difficult.In this paper,ten particles in an entangled state are used as a four-body quantum entanglement channel.Under this channel,the fidelity of the cloned output state can achieve the maximum value of 2/3.In this paper,the entanglement degree of the cloned output state under this universal scheme is calculated.The result of the cloning is that the entanglement degree of the particles is relatively high.When the input state is a GHZ state,the entanglement degree of the output state reaches the maximum value of 1.At the same time,the curve of the entanglement degree of the output state changing with the entanglement degree of the input state is given.This paper studies the remote quantum cloning of the four-body entangled state.The quantum channel established in the scheme and the logical operations taken during the cloning recovery phase may have reference significance for the subsequent more complex quantum cloning research. |
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