  We study the exact decoherence dynamics of the entangled squeezed state of
two single-mode optical fields interacting with two independent and
uncorrelated environments. We analyze in detail the non-Markovian effects on
the entanglement evolution of the initially entangled squeezed state for
different environmental correlation time scales. We find that the environments
have dual actions on the system: backaction and dissipation. In mparticular,
when the environmental correlation time scale is comparable to the time scale
for significant change in the system, the backaction would counteract the
dissipative effect. Interestingly, this results in the survival of some
residual entanglement in the final steady state.
