Quantum Correlations Between Two Atoms In Two Coupled Cavities

Quantum information science is a rapidly developing area of interdisciplinary investigation at the nexus of quantum mechanics and information theory. It now plays a signficant role in a number of subdisciplines of physics, information technology, and engineering.The entanglement makes possible tasks in quantum information which are impossible without it. However, entanglement is not the only type of correlation useful for quantum technology. Recently, it was found that there are some quantum correlations other than entan-glement that also offer some advantage, such as quantum discord, a kind of quantum correlation. In general, this correlation is different from entanglement, and quantum discord may be nonzero even for certain separable states. But Quantum discord is not always larger than entanglement, so quantum discord is not simply a sum of entanglement and some other nonclassical correlation. Some people propose the concept of quantum consonance, which is a measure of nonlocal coherence. The quantum consonance can define as a sum of entangleme-nt and some other nonclassical correlation. In order to compare these three kind of quantum correlation, In this paper, we mainly study three kinds of quantum correlations between Two Atoms in Two Coupled Cavities, and we also study the influence to the three kind of quantum correlations when the coupled strength changed.The paper is organized as follows. In Chap.1, we give a brief introduction of three kind of quantum correlations. In Chap.2, we introduce the judgment of quantum entanglement first, than we introduce a kind of measurement of quantum entanglement:concurrence. In Chap.3, we introduce the concept of quantum discord and quantum consonance, and some foundation of them. In Chap.4, we derive the time dependent quantum discord, quantum consonance and concurrence in this system if initiated from two typical Bell states, the discussions are made and conclusion is given.