Finite temperature quantum correlations in $SU(2)_c$ quark states and quantum spin models

The entanglement at finite temperatures are analyzed by using thermal models for colored quarks making up the hadron physical states. We have found that these quantum correlations entirely vanish at $T_c\geq m_q/\ln(1.5)$. For temperatures larger than $T_c$ the correlations are classical. Also we worked out the entanglement for the transverse Ising spin chain. In dependence on both temperature $T$ and transverse field $\lambda$ 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 ground state.