  Recently, along with the development of quantum information, quantum
entanglemant became a hot topic of people. Quantum entanglemant is one of the
most amazing phenomenon in quantum mechanics that is totally different from
classical physics. However, system would interact with environment in the
practical quantum information process. The entanglement would be broken. In
this paper, we study the disentanglement evolution of three spin qubits in an
XY spin-chain environment. The dynamical process of the disentanglement is
investigated. We found the exact expression of the coherence factor. We discuss
the coherence factor and the parameters, and then we illustrate that the
disentanglement of central spins is best enhanced by the quantum critical
behavior of the environmental spin chain. Furthermore, a scaling rule is
obtained.
