Characterization of partial positive transposition states and measures of entanglement
W. A. Majewski, Takashi Matsuoka, Masanori Ohya · Journal of Mathematical Physics · 2009
A detailed characterization of partial positive transposition (PPT) states, both in the Heisenberg and in the Schrödinger picture, is given. Measures of entanglement are defined and discussed in details. Illustrative examples are provided.