Quantum demultiplexer of quantum parameter-estimation information in quantum networks
The quantum demultiplexer is constructed by a series of unitary operators and multipartite entangled states. It is used to realize information broadcasting from an input node to multiple output nodes in quantum networks. The scheme of quantum network communication with respect to phase estimation is put forward through the demultiplexer subjected to amplitude damping noises. The generalized partial measurements can be applied to protect the transferring efficiency from environmental noises in the protocol. It is found out that there are some optimal coherent states which can be prepared to enhance the transmission of phase estimation. The dynamics of state fidelity and quantum Fisher information are investigated to evaluate the feasibility of the network communication. While the state fidelity deteriorates rapidly, the quantum Fisher information can be enhanced to a maximum value and then decreases slowly. The memory effect of the environment induces the oscillations of fidelity and quantum Fisher information. The adjustment of the strength of partial measurements is helpful to increase quantum Fisher information.
KeywordsQuantum demultiplexer Network communication Quantum Fisher information Partial measurements
This work is supported by the National Natural Science Foundation of Jiangsu Province under Grant No. BK20170376, the Innovation Project of Graduate Education of Jiangsu Province No. JGLX15-150, the Qing Lan Project of Jiangsu Province and the Graduate Creative Projects in USTS No. SKYCX16-015 and No. SKCX5-06.
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