Protecting qubit-qutrit entanglement from amplitude damping decoherence via weak measurement and reversal

We investigate the entanglement protection of a hybrid qubit-qutrit system under amplitude damping decoherence by employing weak measurement and reversal. We examine two typical families of initially entangled qubit-qutrit states (i.e. one-parameter and two-parameter qubit-qutrit states). We find that the qubit-qutrit entanglement decays monotonically as the decoherence strength increases, and may go through a sudden death for some initial states. However, we can completely defeat amplitude damping decoherence and recover the initial entanglement perfectly for any initial states by means of the combination of prior weak measurement and subsequent optimal weak measurement reversal. The only price that we have to pay is the very low success probability.