Finite Temperature Quantum Correlations in SU(2)c Quark States and Quantum Spin Models

The entanglement at finite temperatures is analyzed by using thermal models for colored quarks making up the hadron physical states. We have found that these quantum correlations entirely vanish at Tc ≥ mq/ln(1.5). For temperatures larger than Tc the correlations are classical. We have also worked out the entanglement for the transverse Ising spin chain. In dependence on both temperature T and transverse field λ we can identify a certain region, where the quantum effects are likely to dominate the system. We suggest the mutual information as a quantitative measure for the correlations in the ground state. (author)