Quantum systems have started to emerge as a disruptive technology and enabling platforms - exploiting the principles of quantum mechanics via programmable quantum bits (QuBits) - to achieve quantum supremacy in computing. Academic research, industrial projects (e.g., Amazon Braket, IBM Qiskit), and consortiums like 'Quantum Flagship' are striving to develop practically capable and commercially viable quantum computing (QC) systems and technologies. Quantum Computing as a Service (QCaaS) is viewed as a solution attuned to the philosophy of service-orientation that can offer QC resources and platforms, as utility computing, to individuals and organisations who do not own quantum computers. This research investigates a process-centric and architecture-driven approach to offer a software engineering perspective on enabling QCaaS - a.k.a quantum service-orientation. We employed a two-phase research method comprising (a) a systematic mapping study and (b) an architecture-based development, first to identify the phases of the quantum service development life cycle and subsequently to integrate these phases into a reference architecture that supports QCaaS. The SMS process retrieved a collection of potentially relevant research literature and based on a multi-step selection and qualitative assessment, we selected 41 peer-reviewed studies to answer three RQs. The RQs investigate (i) demographic details in terms of frequency, types, and trends of research, (ii) phases of quantum service development lifecycle to derive a reference architecture for conception, modeling, assembly, and deployment of services, and (iii) The results identify a 4-phased development lifecycle along with quantum significant requirements (QSRs), various modeling notations, catalogue of patterns, programming languages, and deployment platforms that can be integrated in a layered reference architecture to engineer QCaaS.

翻译：量子系统已开始作为一种颠覆性技术和赋能平台出现——通过可编程量子比特（QuBits）利用量子力学原理——以实现计算领域的量子霸权。学术研究、工业项目（如Amazon Braket、IBM Qiskit）以及"量子旗舰"等联盟正致力于开发具备实际能力且商业可行的量子计算系统与技术。量子计算即服务被视为契合面向服务理念的解决方案，能够以效用计算的形式为不拥有量子计算机的个人和组织提供量子计算资源与平台。本研究从软件工程视角出发，探讨以流程为中心、架构驱动的方法来实现QCaaS（亦称量子服务导向）。我们采用包含（a）系统性图谱研究和（b）基于架构开发的两阶段研究方法，首先识别量子服务开发生命周期的各阶段，进而将这些阶段整合到支持QCaaS的参考架构中。系统性图谱研究过程检索了潜在相关的研究文献集合，通过多步骤筛选与定性评估，最终选取41篇同行评审研究来回答三个研究问题。研究问题聚焦于：（i）研究频率、类型与趋势的人口统计学特征；（ii）量子服务开发生命周期各阶段，以推导出用于服务构思、建模、组装与部署的参考架构；（iii）研究结果识别出包含四个阶段的开发生命周期，以及量子关键需求、多种建模符号、模式目录、编程语言和部署平台，这些要素可集成到分层参考架构中以实现量子计算即服务的工程化。