Entanglement engineering of a close bipartite atomic system in a dissipative environment

We investigate the entanglement dynamics of a bipartite atomic system, with atoms being close together, interacting with a common vacuum reservoir. We show that local unitary operations such as Pauli-x and Pauli-z on single or both atoms can lead to a significant positive change in the subsequent evolution of the entanglement. Sudden death of the entanglement can be delayed and even can be avoided by such unitary operations at some suitable times.