  We investigate the dynamics of quantum discord and entanglement for two
central spin qubits coupled to an isotropic Lipkin-Meshkov-Glick bath. It is
found that both quantum discord and entanglement have quite distinct behaviors
with respect to the two different phases of the bath. In the case of the
symmetry broken phase bath, quantum discord and entanglement can remain as
constant. In the case of the symmetric phase bath, quantum discord and
entanglement always periodically oscillate with time. The critical point of
quantum phase transition of the bath can be revealed clearly by the distinct
behaviors of quantum correlations. Furthermore, it is observed that quantum
discord is significantly enhanced during the evolution while entanglement
periodically vanishes.
