Canonical Form and Separability of PPT States in 2x2x2xN Composite Quantum Systems

Abstract

We give a canonical form of PPT states in ${\cal C}^2 \otimes {\cal C}^2\otimes {\cal C}^2 \otimes {\cal C}^N$ with rank=$N$. From this canonical form a necessary separable condition for these states is presented.

Latex, 8 pages