Key Laboratory of Quantum Information, University of Science and Technology of China, CAS, Hefei 230026, China.
Nat Commun. 2010 Apr 12;1:7. doi: 10.1038/ncomms1005.
It is well known that many operations in quantum information processing depend largely on a special kind of quantum correlation, that is, entanglement. However, there are also quantum tasks that display the quantum advantage without entanglement. Distinguishing classical and quantum correlations in quantum systems is therefore of both fundamental and practical importance. In consideration of the unavoidable interaction between correlated systems and the environment, understanding the dynamics of correlations would stimulate great interest. In this study, we investigate the dynamics of different kinds of bipartite correlations in an all-optical experimental setup. The sudden change in behaviour in the decay rates of correlations and their immunity against certain decoherences are shown. Moreover, quantum correlation is observed to be larger than classical correlation, which disproves the early conjecture that classical correlation is always greater than quantum correlation. Our observations may be important for quantum information processing.
众所周知，许多量子信息处理操作在很大程度上依赖于一种特殊的量子相关性，即纠缠。然而，也有一些量子任务在没有纠缠的情况下表现出量子优势。因此，区分量子系统中的经典和量子相关性具有重要的基础和实际意义。考虑到相关系统与环境之间不可避免的相互作用，理解相关性的动力学将引起极大的兴趣。在这项研究中，我们在全光学实验装置中研究了不同种类的双体相关性的动力学。我们展示了相关性的衰减率的行为的突然变化及其对某些退相干的免疫力。此外，我们观察到量子相关性大于经典相关性，这推翻了早期的猜想，即经典相关性总是大于量子相关性。我们的观察结果可能对量子信息处理很重要。
