Quantum circuit debugging and sensitivity analysis via local inversions

As the width and depth of quantum circuits implemented by state-of-the-art quantum pro-cessors rapidly increase, circuit analysis and as-sessment via classical simulation are becoming unfeasible. It is crucial, therefore, to develop new methods to identify significant error sources in large and complex quantum circuits. In this work, we present a technique that pinpoints the sections of a quantum circuit that affect the cir-cuit output the most and thus helps to identify the most significant sources of error. The tech-nique requires no classical verification of the cir-cuit output and is thus a scalable tool for de-bugging large quantum programs in the form of circuits. We demonstrate the practicality and efficacy of the proposed technique by applying it to example algorithmic circuits implemented on IBM quantum machines.