Quantum Computing needs Classical Software

To unlock the full potential of quantum computing, the eld must develop a robust software ecosystem grounded in classical software engineering principles—a discipline that itself needs to be adapted to the quantum domain. Currently, however, the advancement of quantum computing is hampered by a growing “software gap,” where a fragmented and non-standardized ecosystem of tools hinders progress. Much of the existing quantum software originates from academic proofs-of-concept that often lack the robustness, maintainability, and scalability required for practical applications. This article argues that bridging this gap requires the systematic application of principles from classical software engineering and design automation. We present the Munich Quantum Toolkit (MQT) as a case study, showcasing a suite of open-source tools built on these principles. By tracing its evolution, we distill key lessons learned in testing, deployment, and community-driven development. We demon-strate that adopting a rigorous software engineering culture is essential for building the reliable and sustainable software infrastructure needed to unlock the full potential of quantum computing.