Multiple transitions entangled--separable in thermal equilibrium states in thermal equilibrium states

ANALÍA ZWICK, OMAR OSENDA, GUIDO RAGGIO

Rio de Janeiro, Brasil

Congreso; International Congress on Mathematical Physics - ICMP2006; 2006

International Association of Mathematical Physics

 We introduce characteristic, viz. critical, temperatures marking transitions fromentanglement to separability or vice versa. We present examples for the various possible thermal entanglement scenarios, resulting from the presence of several transitions,  in bipartite qubit/qutrit systems and bipartite sub--systems of larger ones. It is shown (in one of the examples) that concave, continuous, real valued functions of the state  do not detect the aforementioned transitions