FGQT Q05 Quantum Technologies Use Cases [written by the CEN-CENELEC Focus Group on Quantum Technologies (FGQT)]

Quantum technologies form a booming field of research areas. Often, we subdivide the field of quantum technologies in quantum computing, quantum communication and quantum sensing. Some also include a fourth: quantum simulation. Each of them has a different level of maturity and therefore different standardization needs. Standards can help mature a field and allow for interoperability of different devices or parts of a larger device. Especially in the field of quantum technologies, we expect only a small number of parties to be able to manufacture the hardware by themselves. More likely is that a party focuses on only a small part of the hardware or software stack. The output of the products of these parties has to interoperate with the input and/or output of the products of other parties. The standardization needs and the level of maturity of specific quantum applications may be uncorrelated. Furthermore, it might be difficult to directly define standards for some application. Instead, use cases allow to freely think about some application and how it should interact with the outside world and with other components of a larger system and which interfaces are necessary. From this, we can determine where which standards are needed when and the characteristics of this use-case. Even though use cases can imply standards or standardization needs, they not have to. Use cases are relevant on their own as they give a sense of what the community is interested in and what applications of quantum technologies are possible. The use cases presented in this document are unstructured, both in topic and in the readiness or implication on standardization. Each subsection contains a separate use case and starts with a description, enabling technologies and standardization needs. Some use cases follow with a deeper discussion of the spects where standards are needed or might be beneficial.