Automatically Refining Assertions for Efficient Debugging of Quantum Programs

Abstract: As new advancements in the field of quantum computing lead to the development of increasingly complex programs, approaches to validate and debug these programs are becoming more important. To this end, methods employed in classical debugging, such as assertions for testing specific properties of a program's state, have been adapted for quantum programs. However, to efficiently debug quantum programs, it is key to properly place these assertions. This usually requires a deep understanding of the program's underlying mathematical properties, constituting a time-consuming manual task for developers. To address this problem, this work proposes methods for automatically refining assertions in quantum programs by moving them to more favorable positions in the program or by placing new assertions that help to further narrow down potential error locations. This allows developers to take advantage of rich and expressive assertions that greatly improve the debugging experience without requiring them to place these assertions manually in an otherwise tedious manner. An open-source implementation of the proposed methods is available at https://github.com/cdatum/mqt-debugger.