Quantum correlations in critical XXZ system and LMG model

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 Δ=−1. However, only information deficit and local quantum uncertainty can demonstrate quantum phase transitions at Δ=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.