nt - p h / 06 04 02 0 v 1 5 A pr 2 00 6 Entanglement dynamics of qubits in a common environment

The entanglement dynamics of a quantum register with two or three two-level atoms interacting with a common environment is analytically studied by the quantum jump method. In contrast to the usual belief that the environment plays a role of destroying the entanglement, it is found that the environment can also produce stable entanglement between the qubits that are prepared initially in a separable state. Our study indicates how the environment noise produces the entanglement in manner of incoherence and emphasizes the constructive role played by the environment in certain tasks of quantum information processing.