Entangled states with positive partial transposes arising from indecomposable positive linear maps
by Kil-Chan Ha, Seung-Hyeok Kye and Young Sung Park
Phys. Lett. A, 313 (2003), 163-174.

We construct entangled states with positive partial transposes using indecomposable positive linear maps between matrix algebras. We also exhibit concrete examples of entangled states with positive partial transposes arising in this way, and show that they generate extreme rays in the cone of all positive semi-definite matrices with positive partial transposes. They also have Schmidt numbers two.

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