Derivation of the robustness from the concurrence

Abstract

Adding the maximally mixed state with some weight to the entanglement system leads to disentanglement of the latter. For each predefined entangled state there exists a minimal value of this weight for which the system loses its entanglement properties. These values were proposed to be used as a quantitative measure of entanglement called robustness [G. Vidal and R. Tarrach, Phys. Rev. A 59, 141 (1999)]. Using the concurrence, we propose the derivation of this measure for the system of two-qubit. Namely, for a two-qubit pure state, an exact expression of robustness is obtained. Finally, in the same way, the robustness of special cases of mixed two-qubit states is calculated.

14 pages

References in corpus (5)

• Experimental quantum teleportation
• Entanglement universality of two-qubit X-states
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Cited by in corpus (3)

• Sensitivity of entanglement measures in bipartite pure quantum states
• Entanglement and entropy in multipartite systems: a useful approach
• Optimizing entanglement in two-qubit systems