Modified Grover operator for quantum amplitude estimation

Abstract In this paper, we propose a quantum amplitude estimation method that uses modified Grover operator and quadratically improves the accuracy in ideal case, as conventional one using standard operator. Under depolarizing noise, proposed can outperform sense it principle achieve ultimate characterized by Fisher information limit of large number qubits, while cannot same value accuracy. general superiority requires sophisticated adaptive measurement, but numerically demonstrate approach to accuracy, even with simple non-adaptive measurement strategy.