The geometry of bipartite qutrits including bound entanglement

We investigate the state space of bipartite qutrits, in particular we construct an analog to the magic tetrahedron for bipartite qubits-a magic simplex W. Due to the high symmetry it is enough to consider certain typical slices through W and optimal entanglement witnesses can be calculated. A whole region of bound entangled states is found. (C) 2007 Elsevier B.V. All rights reserved.