Revival and decay of entanglement in a two-qubit system coupled to a kicked top

We investigate the entanglement dynamics of a two-qubit system coupling to a spin environment, described by a quantum kicked top (KT). The entanglement of the two-qubit system is sensitive to the classical orbit of the KT and displays rich dynamic behaviors. It quickly vanishes for chaotic orbit, but has significant revivals after the death when the KT is classically regular. As the tori of the KT shrink, the concurrence decay of the system is weakened and the concurrence revival of the system is strengthened. Such phenomena are analyzed in the literature of the interaction picture and the dynamics of wavepacket. It is found that the decay and revival of the concurrence of the system is closely related to the periodic motion of the wavepacket.