有噪量子信道中的量子相干性

Quantum coherence over the noisy quantum channels

量子态的相干叠加是量子力学的重要特征,同时也是量子计算能够实施的重要资源.由于噪声的影响,量子比特系统的相干性不能长时间的保持.有噪量子信道能够多大程度的保持量子相干性?本文利用相对熵相干性度量,首先讨论两体量子系统相干性、纠缠以及量子关联之间的关系.然后讨论噪声对相干性的影响.通过定义最大相干性的衰减量,即相干性衰减,进而讨论相干性衰减与系统和环境之间纠缠的不确定性关系.最后,具体讨论几类常见量子信道保持最大相干性的能力.

The coherent superposition of quantum states is one of the characteristic features of quantum mechanics, and it is also physical resource of quantum information processing. The coherence of quantum system can not last a long time as the effect of the noise. How well has the noisy channel preserved the quantum coherence of the quantum system？ Based on the relative entropy of coherence, in this paper, we discuss the coherence, entanglement and quantum correlations in the bipartite quantum system. To discuss the effect of the noise, we then give a definition of the decayed amount of the maximal quantum coherence, i.e., the decay of coherence. Then we obtain that the uncertainty relations between entanglement and the coherence with respect to the noisy models. Finally, we used the measure of the decay of coherence to discuss how well several noisy channels preserves the coherence.