Entanglement in thermal equilibrium states
Omar Osenda, G. A. Raggio · Physical Review A · 2005
We reconsider the problem of entanglement of thermal equilibrium states of composite systems. We introduce characteristic, viz., critical, temperatures---and bounds for them---marking transitions from entanglement to separability, or vice versa. We present examples for the various possible thermal entanglement scenarios in bipartite qubit-qubit and qubit-qutrit systems.