Environment-assisted quantum state and distribution entanglement restoration in spin chain

We propose a novel scheme to realize perfect state transfer and entanglement distribution in the spin chain. With the assistance of environment-assisted measurement, we get the exact analytical expression of the optimal final restoration, show that the quantum state and distribution entanglement can exactly be recovered with a certain probability, i.e. the fidelity of a general pure state can reach 100%, which is independent of the size of the spin chain. Comparing with the results obtained by the method of weak measurement, our results show notable superiorities on restoration scope and success probability.