2005/09/30 by A. R. Usha Devi, M. S. Uma, R. Prabhu +1 · 1 citation
Physics and Astronomy · #quant-ph
paper · pdf · doi:10.1142/s0217979206034406
published as Int. J. Mod. Phys. B, Vol. 20, (2006) 1917-1933 · 9 pages, 2 figures, REVTEX, Replaced with a published version
arxiv created 2006/06/23 · arxiv updated 2009/12/01
Pairwise entanglement properties of a symmetric multi-qubit system are analyzed through a complete set of two-qubit local invariants. Collective features of entanglement, such as spin squeezing, are expressed in terms of invariants and a classifcation scheme for pairwise entanglement is proposed. The invariant criteria given here are shown to be related to the recently proposed (Phys. Rev. Lett. 95, 120502 (2005)) generalized spin squeezing inequalities for pairwise entanglement in symmetric multi-qubit states.