Protecting genuine tripartite nonlocality by weak measurement and quantum measurement reversal.

We use weak measurement (WM) and quantum measurement reversal (QMR) techniques to suppress the degradation of genuine nonlocality of a special class of three-qubit "X" states when they suffer from the amplitude damping noise. We choose the maximal violation of the Svetlichny inequality to quantify the genuine nonlocality of states in this paper. We analyse mathematically the sufficient and necessary condition for weak measurement or QMR to enhance the genuine nonlocality of such "X" states. We propose a specific protection scheme combined WM with QMR for such states, and calculate the maximal genuine nonlocality reached by our scheme as well as the success probability. We apply our scheme to the GHZ-like states and the Werner-type states to show the protection effect. [ABSTRACT FROM AUTHOR]