1106.3392 (Faisal A. A. El-Orany)

Is the average of the spin-correlation elements the real measure of the
entanglement of the two-qubit systems?    [PDF]

Faisal A. A. El-Orany

Based on the Pauli spin operators we develop the notion of the spin-correlation matrix for the two-qubit system. The measure of the entanglement between the qubits is represented by the average of the non-zero elements of this matrix. This criterion turns out to be a necessary and sufficient condition for the entanglement. The criterion is generic since it works for the mixed and pure systems. Also, it can be easily extended to treat the entanglement of the multipartite systems. We compare the results obtained from this criterion with those from concurrence for various examples. The sudden-death of entanglement phenomenon has not been realized in terms of the new criterion. We believe that this criterion may have a wide range of potential applications.

View original: http://arxiv.org/abs/1106.3392