QuSema uses quantum semantics as a source-level oracle to relocate 20 historical silent bugs and surface 40 maintainer-confirmed new bugs in Qiskit and PennyLane
The authors present QuSema, an autonomous testing agent that uses quantum semantics and documentation as a source-level semantic oracle, running a three-stage loop of contextual unit preparation, semantic defect detection, and library API triggering and validation to decide whether implementation logic can turn valid inputs into invalid outputs; on a benchmark of 20 historical silent bugs in Qiskit and PennyLane it achieves higher mean bug relocation counts than Claude Code and Codex, and it discovers 40 previously unknown bugs confirmed by maintainers, 30 of them silent.