Quantum gate verification and its application in property testing

To guarantee the normal functioning of quantum devices in different scenarios, appropriate benchmarking tool kits are quite significant. Inspired by the recent progress on quantum state verification, here we establish a general framework of verifying a target unitary gate. In both the nonadversarial and adversarial scenarios, we provide efficient methods to evaluate the performance of verification strategies for any qudit unitary gate. Furthermore, we figure out the optimal strategy and its realization with the prepare-and-measurement setting. Specifically, for the commonly used quantum gates like single-qubit and qudit gates, multiqubit Clifford gates, and multiqubit generalized controlled-Z(X) gates, we provide efficient local verification protocols. Besides, we discuss the application of gate verification to the detection of entanglement-preserving property of quantum channels, and further quantify the robustness measure of them. We believe that the gate verification is a promising way to benchmark a large-scale quantum circuit as well as to test its property.