Entanglement Protection about Four-Particle Cluster State

In the manuscript, we proposed three entanglement protection schemes with environment-assisted measurements and weak measurement reversals. The result demonstrates that the entanglement of four-particle cluster state is disturbed by the amplitude damping channel, but the weak measurement reversal operation helps to preserve the entanglement of the final output quantum state. In particular, the entanglement will reach the maximum if the weak measurement reversal strength is equal to the amplitude damping magnitude. Compared with the previous protection protocols, the performance of our schemes is more practical.