We generalize the W class of states from n qubits to n qudits and prove that their entanglement is fully characterized by their partial entanglements even for the case of the mixture that consists of a W-class state and a product state |0〉. PACS numbers: 03.67.-a, 03.65.Ud, Generalized W-Class State and its Monogamy Relation 2

We derive monogamy relations (tradeoffs) between strengths of violations of Bell's inequalities from the nonsignaling condition. Our result applies to general Bell inequalities with an arbitrary large number of partners, outcomes, and measurement settings. The method is simple, efficient, and does not require linear programing. The results are used to derive optimal fidelity for asymmetric clon...

We study the concurrence of four-qubit quantum states and provide analytical lower bounds of concurrence in terms of the monogamy inequality of concurrence for qubit systems. It is shown that these lower bounds are able to improve the existing bounds and detect entanglement better. The approach is generalized to arbitrary qubit systems.

The impossibility of perfect cloning and state estimation are two fundamental results in quantum mechanics. It has been conjectured that quantum cloning becomes equivalent to state estimation in the asymptotic regime where the number of clones tends to infinity. We prove this conjecture using two known results of quantum information theory: the monogamy of quantum correlations and the propertie...

We have introduced a new class of multipartite entangled mixed states with pure state de-compositions of generalized W states, similar to SC states having generalized GHZ states in the pure state decomposition. The entanglement and separability properties are studied according to PPT operations. Monogamy relations related to these states are also investigated .