基于弱测量的噪声环境下量子秘密共享方案

Quantum secret sharing scheme in noise environment based on weak measurement

量子秘密共享是量子密码学中一个重要分支,而纠缠态是设计秘密共享协议的重要手段之一。噪声环境会导致量子纠缠态发生退相干,从而降低方案质量甚至失败。本文针对相关文献中的量子秘密共享方案,研究了振幅阻尼信道对方案的影响。为了减少纠缠退相干的发生,采用了弱测量方法对噪声环境下的方案进行保护,分析了经过振幅阻尼信道作用之后得到的秘密量子态与初始秘密之间的保真度;给出了不采取任何手段时得到秘密与采用弱测量得到秘密时的相干性度量的定量研究。最后,以具体的量子态为例,发现弱测量的方法对提高方案中秘密态的保真度与相干性具有一定的意义。

Quantum secret sharing is an important branch of quantum cryptography and quantum entanglement plays an important role to design the secret sharing protocol. However, under the influence of noise environment, it will lead to the decoherence of the quantum entangled state, and then the quality of the scheme is reduced or even failed. According to the quantum secret sharing scheme in the reference, the effect of amplitude damping channel on the scheme is studied. In order to reduce entanglement decoherence, the weak measurement is used to protect the scheme in noisy environment and analyze the fidelity between the secret by the amplitude damped channel and the initial one. In addition, a quantitative study on the coherence measure between without any means and using weak measurement methods is given. Finally, through the specific quantum state as an example, it is found that the weak measurement has certain significance to improve the fidelity and coherence of the secret state in the scheme.