Recent advances in quantum computing have sparked excitement that this new computing paradigm could solve previously intractable problems. However, due to the faulty nature of current quantum hardware and quantum-intrinsic noise, the full potential of quantum computing is still years away. Hybrid quantum-classical computing has emerged as a possible compromise that achieves the best of both worlds. In this paper, we look at hybrid quantum-classical computing from a software engineering perspective and present the first empirical study focused on characterizing and evaluating recurrent issues faced by developers of hybrid quantum-classical applications. The study comprised a thorough analysis of 531 real-world issues faced by developers -- including software faults, hardware failures, quantum library errors, and developer mistakes -- documented in discussion threads from forums dedicated to quantum computing. By qualitatively analyzing such forum threads, we derive a comprehensive taxonomy of recurring issues in hybrid quantum-classical applications that can be used by both application and platform developers to improve the reliability of hybrid applications. The study considered how these recurring issues manifest and their causes, determining that hybrid applications are crash-dominant (74% of studied issues) and that errors were predominantly introduced by application developers (70% of issues). We conclude by identifying recurring obstacles for developers of hybrid applications and actionable recommendations to overcome them.

翻译：量子计算的最新进展激发了人们对于这一新计算范式能够解决先前棘手问题的期待。然而，由于当前量子硬件的固有缺陷及量子本征噪声，量子计算的全部潜力仍需数年才能实现。混合量子-经典计算作为一种可能的折中方案应运而生，旨在兼取两者之长。本文从软件工程的视角审视混合量子-经典计算，并首次开展实证研究，重点描述和评估混合量子-经典应用开发者面临的常见问题。本研究对531个真实世界开发者问题进行了深入分析——包括软件故障、硬件失效、量子库错误及开发者失误——这些问题记录在量子计算专业论坛的讨论帖中。通过对这些论坛帖进行定性分析，我们推导出一个关于混合量子-经典应用中重复性问题的全面分类体系，可供应用开发者和平台开发者共同使用，以提升混合应用的可靠性。研究考察了这些重复性问题的表现形式及其成因，确定混合应用以崩溃为主导（占研究问题的74%），且错误主要由应用开发者引入（占问题的70%）。最后，我们识别了混合应用开发者面临的常见障碍，并提出了可操作的改进建议。