[en] We investigate monogamy relations related to quantum entanglement for n-qubit quantum systems. General monogamy inequalities are presented to the $\mathrm{\beta <!--\; ??\; -->}\text{th}(\mathrm{\beta <!--\; ??\; -->}\in <!--\; ???\; -->(0,2))$ power of concurrence, negativity and the convex-roof extended negativity, as well as the $\mathrm{\beta <!--\; ??\; -->}\text{th}(\mathrm{\beta <!--\; ??\; -->}\in <!--\; ???\; -->(0,\sqrt{2}))$ power of entanglement of formation. These monogamy relations are complementary to the existing ones with different regions of parameter $\mathrm{\beta <!--\; ??\; -->}$. In additions, new monogamy relations are also derived which include the existing ones as special cases.

[en] Quantum correlations characterized by quantum entanglement and quantum discord play important roles in many quantum information processing. We study the relations among the entanglement of formation, concurrence, tangle, linear entropy-based classical correlation and von Neumann entropy-based classical correlation . We present analytical formulae of linear entropy-based classical correlation for arbitrary $d\otimes <!--\; ???\; -->2$ quantum states and von Neumann entropy-based classical correlation for arbitrary $2\otimes <!--\; ???\; -->2$ rank-2 quantum states. From the von Neumann entropy-based classical correlation, we derive an explicit formula of quantum discord for arbitrary rank-2 two-qubit quantum states.

[en] We present a lower bound of concurrence for four-partite systems in terms of the concurrence for $M(2\le <!--\; ???\; -->M\le <!--\; ???\; -->3)$ part quantum systems and give an analytical lower bound for $2\otimes <!--\; ???\; -->2\otimes <!--\; ???\; -->2\otimes <!--\; ???\; -->2$ mixed quantum sates. It is shown that these lower bounds are able to improve the existing bounds and detect entanglement better. Furthermore, our approach can be generalized to multipartite quantum systems.

[en] We study monogamy relations for arbitrary dimensional multipartite systems. Monogamy relations based on concurrence and concurrence of assistance for any dimensional $m_1\otimes <!--\; ???\; -->m_2\otimes <!--\; ???\; -->\cdots <!--\; ???\; -->\otimes <!--\; ???\; -->m_N$ quantum states are derived, which give rise to the restrictions on the entanglement distributions among the subsystems. Besides, we give the lower bound of concurrence for four-partite mixed states. The approach can be readily generalized to arbitrary multipartite systems.

[en] We present a family of coherence quantifiers based on the generalized $\mathrm{\alpha <!--\; ??\; -->}$–z-relative R$\stackrel{´<!--\; ??\; -->}{e}$nyi entropy. These quantifiers satisfy all the standard criteria for well-defined measures of coherence and include some existing coherence measures as special cases.

[en] We study the concurrence of arbitrary dimensional multipartite quantum systems. An explicit analytical lower bound of concurrence for four-partite mixed states is obtained in terms of the concurrences of tripartite mixed states. Detailed examples are given to show that our lower bounds improve the existing lower bounds of concurrence. The approach is generalized to five-partite quantum systems.

[en] We present a lower bound of concurrence for arbitrary-dimensional bipartite quantum states. This lower bound may be used to improve all the known lower bounds of concurrence. Moreover, the lower bound gives rise to an operational sufficient criterion of distillability of quantum entanglement. The significance of our result is illustrated by quantitative evaluation of entanglement for entangled states that fail to be identified by the usual concurrence estimation method and by showing the distillability of mixed states that cannot be recognized by other distillability criteria.