1208.2706 (S. M. Hashemi Rafsanjani et al.)

Genuinely Multipartite Concurrence of N-qubit X-matrices    [PDF]

S. M. Hashemi Rafsanjani, M. Huber, C. J. Broadbent, J. H. Eberly

We find an algebraic formula for the N-partite concurrence of N qubits in an X-matrix. X- matricies are density matrices whose only non-zero elements are diagonal or anti-diagonal when written in an orthonormal basis. We use our formula to study the dynamics of the N-partite entanglement of N remote qubits in generalized N-party Greenberger-Horne-Zeilinger (GHZ) states. We study the case when each qubit interacts with a partner harmonic oscillator. It is shown that only one type of GHZ state is prone to entanglement sudden death; for the rest, N-partite entanglement dies out momentarily. Algebraic formulas for the entanglement dynamics are given in both cases.

View original: http://arxiv.org/abs/1208.2706