The entanglement dynamics of a two-qutrit system under decoherence from a spin environment is investigated by using negativity as entanglement measure. Our results imply that the entanglement evolution depends not only on the coupling strength and the tunneling elements of the environment but also on the number of the freedom degrees and the initial state of the environment. entanglement dynamics, quantum decoherence, a spin environment PACS: 03.67.Mn, 03.65.Yz

The effect of stochastic dephasing on the dynamics of entanglement of qutrit-qutrit states is investigated by using negativity and bound entanglement defined with realignment criterion. From the analysis, we find that the time evolution of quantum free entanglement and bound entanglement depends on the fluctuations of the stochastic variables and the parameters of the particular initial states of concern. Our results imply that some qutrits states display both distillability sudden death and entanglement sudden death, while some states do not display distillability sudden death but only entanglement sudden death.