Quantum correlations in critical $XXZ$ system and LMG model (1805.02386v1)

Abstract: We investigate the quantum phase transitions for the $XXZ$ spin-1/2 chains via the quantum correlations between the nearest and next to nearest neighbor spins characterized by negativity, information deficit, trace distance discord and local quantum uncertainty. It is shown that all these correlations exhibit the quantum phase transitions at $\Delta=-1$. However, only information deficit and local quantum uncertainty can demonstrate quantum phase transitions at $\Delta=1$. The analytical and numerical behaviors of the quantum correlations for the $XXZ$ system are presented. We also consider quantum correlations in the Hartree-Fock ground state of the Lipkin-Meshkov-Glick (LMG) model.