We investigate the dissipative dynamics of quantum discord in a decoherence
model with two initially entangled qubits in addition to a quantum kicked top.
The two qubits are uncoupled during the period of our study and one of them
interacts with the quantum kicked top. We find that the long time behavior of
quantum discord could be well described by the fidelity decay of the quantum
kicked top; for short time behavior, however, the phase of the amplitude of the
fidelity decay is necessary to provide more specific information about the
system. We have made comparison between the quantum kicked top and multi-mode
oscillator system in describing environment, and also compared the dynamics of
the entanglement with that of quantum discord.Comment: 5 pages, 3 figures, and Accepted by Europhysics Letter
