全息检测中的焦散线现象与干涉条纹的关系

在实时全息干涉计量实验中，当试件负荷甚大时，干涉条纹中会出现一些阴影区，它们在试件破裂过程中起重要作用。当负荷接近试件断裂强度时，可清晰看到并记录下阴影区的延伸、分叉、扩展直至试件破裂的过程。这些阴影区实际上就是几何光学中的焦散线现象。应用此现象可以计算应力强度因子。介绍了在寻找全息干涉条纹与应力强度因子之间关系所作的研究，导出了干涉条纹最大值与应力强度因子之间的定量关系式。从而，为使用全息法与焦散线法相结合的检测方法提供了定量计算的基础。     

Measures of genuine multipartite entanglement for graph states

Graph states are special multipartite entangled states that have been proven useful in a variety of quantum information tasks. We address the issue of characterizing and quantifying the genuine multipartite entanglement of graph states up to eight qubits. The entanglement measures used are the geometric measure, the relative entropy of entanglement, and the logarithmic robustness, have been proved to be equal for the genuine entanglement of a graph state. We provide upper and lower bounds as well as an iterative algorithm to determine the genuine multipartite entanglement.