We derive an analytical lower bound for the concurrence of a bipartite quantum state in arbitrary dimension. A functional relation is established relating concurrence, the Peres-Horodecki criterion, and the realignment criterion. We demonstrate that our bound is exact for some mixed quantum states. The significance of our method is illustrated by giving a quantitative evaluation of entanglement...

We show that although we can not distill a singlet from many pairs of bound entangled states, the concurrence and tangle of two entangled quantum states are always strictly larger than that of one, even both entangled quantum states are bound entangled. We present a relation between the concurrence and the fidelity of optimal teleportation. We also give new upper and lower bounds for concurrenc...

We obtain Lewenstein-Sanpera decomposition of iso-concurrence decomposable states of 2⊗2 quantum systems. It is shown that in these systems average concurrence of the decomposition is equal to the concurrence of the state and also it is equal to the amount of violation of positive partial transpose criterion. It is also shown that the product states introduced by Wootters in form the best separ...

We establish a relation between the Schwarz inequality and the generalized concurrence of an arbitrary, pure, bipartite or tripartite state. This relation places concurrence in a geometrical and functional-analytical setting.

We propose a minimal entanglement generating set for a general multipartite state based on concurrences classes. In particular, we construct concurrence for general three-partite states based on a redefinition of our concurrence classes. This shows that a measure of entanglement for threepartite states can be decomposed into two different classes that are constructed by two different local oper...

We review the entanglement properties in collective models and their relationship with quantum phase transitions. Focusing on the concurrence, which characterizes the two-spin entanglement, we show that for first-order transitions, this quantity is singular but continuous at the transition point, contrary to the common belief. We also propose a conjecture for the concurrence of arbitrary symmet...