Protecting entanglement under depolarizing noise environment by using weak measurements

Weak measurements can effectively suppress amplitude-damping decoherence. In this paper, we study the effect of this method in protecting the entanglement of two qubits from independent depolarizing noisy channels. Our scheme consists of prior weak measurement on each qubit before the interaction with the noisy channel followed by a post recovering measurement. It is shown that the two-qubit entanglement can be enhanced to an optimal value by performing weak measurement and adjusting measurement parameter on one qubit. The effectiveness of our scheme is more pronounced in improving the two-qubit system with less initial entanglement. In addition, the maximal value of entanglement does not depend on the initial-state parameters.