  We study the exact entanglement dynamics of two qubits interacting with a
common zero-temperature non-Markovian reservoir. We consider the two qubits
initially prepared in Bell-like states or extended Werner-like states. We study
the dependence of the entanglement dynamics on both the degree of purity and
the amount of entanglement of the initial state. We also explore the relation
between the entanglement and the von Neumann entropy dynamics and find that
these two quantities are correlated for initial Bell-like states.
