Enhancing quantum entanglement by means of weak measurement under various environments.

We investigate the relation between dissipation and coherent effects in the dynamics of quantum entanglement (QE) between two qubits by means of weak measurement. Under weak measurement, the increase or decrease of QE closely relates with the dissipation. The amplitude of QE will only be elevated through enhancing the measurement strength in weak correlated or no correlated instantaneous modes, and the entanglement sudden death (ESD) is retarded effectively. In the correlated dephasing mode, however, the amplitude of QE will decrease due to the increases of measurement strength. The periods for entanglement death, as well as the dark and bright in the concurrence are not changed. Therefore, the environmental relevance helps to enhance the amplitude of QE and delay the entanglement death. [ABSTRACT FROM AUTHOR]