Quantum circuit debugging via layer inversion

The rapid advances in quantum computing in the last few years have gotten us closer to the point where verification by classical simulation is not a feasible option anymore for circuit characterization and debugging. In this work, we present a technique inspired by circuit mirroring that identifies the layers of a circuit that affect the circuit output the most, and thus helps to identify the most significant sources of error. The technique requires no classical verification of circuit output and is thus a scalable tool for debugging large quantum programs in the form of circuits. We demonstrate the practicality and efficacy of the proposed technique by applying it to QAOA and QFT circuits implemented on IBM quantum machines.