(De)constructing Quantum Software (DeQS)

Quantum computers need a new kind of software, and today’s tools for writing and checking that software are not up to the job. This project aims to fix that by building better ways to compile high-level quantum algorithms into instructions that real hardware can execute, to simulate quantum computations on classical supercomputers, and to automatically verify whether a quantum calculation is correct. The core problem is that quantum computers are fundamentally different from classical ones. Their software must manage fragile quantum states and obey strict physical constraints, yet current compilers and verification tools are ad hoc and error-prone. This research uses the ZX calculus—a graphical method that represents quantum computations as networks of nodes and wires—to turn software design into a process of simplifying and rearranging those graphs using rigorous rules. If successful, the work could make quantum computers more reliable and practical for tasks like simulating new materials, optimising supply chains, or cracking encryption. But this is primarily fundamental science: it is developing the mathematical and logical foundations for a future quantum software stack. Past work on graphical calculi for quantum theory has already led to unexpected advances in classical circuit optimisation and error correction, so deeper understanding here could open doors that are not yet visible.