Introduction

Since its discovery, quantum physics has helped us understand the universe better than ever before and has resulted in many new devices that depend on that understanding, including the transistor and the laser.

Recently, due to our ever-increasing capability to precisely control individual particles and their physical interactions, we have become able to build new technologies that directly exploit the fundamental principles of quantum physics ^[1]. Our ability to do this is often referred to as the ‘second quantum revolution’ and is enabling the development of devices referred to as ‘quantum technologies’. The applications of quantum technologies are vast, including quantum computing, quantum sensing and timing, and quantum communications and have a number of advantages over their classical (i.e. non-quantum) counterparts.

These advantages can deliver benefits in areas as diverse as environmental monitoring, health care and navigation. The quantum technologies being developed for these applications differ from previous technologies due to their reliance on uniquely quantum effects such as non-determinism and entanglement; these effects may allow such technologies to achieve significant advantages over their classical counterparts in certain applications. The 2023 McKinsey Quantum Technology Monitor indicates a vibrant and flourishing quantum ecosystem. It expects the global quantum computing market to reach $93 billion by 2040, with the overall quantum technology market potential estimated at $106 billion; quantum sensing, timing, imaging, and communications, each have an estimated market size ranging from $1 billion to $7 billion by 2040 ^[3]. The UK’s Quantum Strategy is currently working to realise the advantages quantum technologies offer ^[2].

However, before the advantages of quantum technologies can be realised in practice, quantum technologies must be integrated into wider systems which incorporate both quantum and classical elements ^[4].

The standard approach to engineering applied to modern-day systems, which have become increasingly sophisticated and complex, is referred to as systems engineering. Systems engineering is an interdisciplinary engineering field, which focuses on how to design, integrate, and manage complex systems over their life cycles. This white paper will look at the application of systems engineering to quantum technology, in order to:

1. Highlight some of the challenges that quantum effects will pose to current systems engineering approaches and to explain the potential problems and risks that this may lead to;
2. Propose some initial strategies and actions which can be adopted in order to address these challenges and risks. These approaches are intended to minimise the disruption of this new technology to established systems engineering methodologies, whilst recognising the challenges that are presented to existing systems engineering approaches.

This paper first discusses the development of quantum technologies, before introducing Systems Engineering. This is followed by how SE for classical systems is challenged by introducing quantum technologies. Subsequent sections expand on these challenges before the paper concludes with recommendations.