Combining Viewpoints in Quantum Theory (Ext.)

This is an extension of the Fellowship: Combining Viewpoints in Quantum Theory.

Quantum hardware essentially consists of small quantum-mechanical systems that we can control, used to make nature solve certain problems much more efficiently than any classical hardware could, or even communicate in ways that were plain impossible with classical hardware. Large-scale deployment of quantum technology will clearly transform our society.
One of the main difficulties with this revolution is the steep learning curve to high-level programming of quantum software. The most fundamental dilemma runs straight to the heart of the counterintuitiveness of quantum mechanics: you can only extract data from a quantum system from one classical viewpoint at a time. To learn more about the system, you need to combine measurements from multiple classical viewpoints. But at the same time, quantum computers are so much more powerful than classical ones precisely because of quantum programmers are able to work in, and switch between, different classical viewpoints.

The Fellowship has established a formal framework in which quantum systems and classical viewpoints live on an equal footing in a single category, and studied the dynamical relationships between them. Building on this success, the extension will turn these fundamental results into more practical benefits. First, we will optimise quantum computations by minimising the number of switches of classical viewpoint, in a way that makes the quantum computation as cheap as possible, while at the same time making it as intuitive as possible to program in the first place. This will be implemented in three industry standard quantum programming platforms. Second, we will extend the framework to take spatial aspects into account, to let us specify distributed quantum communication protocols in a realistic way, and allow new ones. This will advance our theoretical understanding of nature. At the same time, it will have practical benefits by making the design of quantum protocols and algorithms more accessible to non-specialist programmers.

The motivation driving this extension is to magnify the Fellowship's impact by developing its foundational results to more practical ends. This will benefit the following groups, in order of descending expected gain.

0. Academics
Needless to say, academic researchers will appreciate the Fellowship extension's technical advances. This impacts a wide range of areas beyond immediate narrow disciplines: quantum computing, programming langauges, category theory, group theory, operator algebra, graph rewriting, relativistic quantum information theory, causality, and security. This group will not only benefit from the Fellowship extension's academic publications, but also from supporting software tools.

1. Quantum computing industry
The main impact goal of the extension is to incorporate the Fellowship's foundational results into the current quantum computing ecosystem. In particular, we will target three specific enterprises that produce platforms that are poised to become industry standards: Microsoft, with its full-stack quantum computing architecture Liquid; Rigetti Computing, with its experimental quantum programming suite Forest; and Dalhousie University, with its open-source embedded scalable functional quantum programming language Quipper. The entire user base of these three platforms will be impacted directly. This will be achieved by prototype implementations ready for uptake, and investigating hosting PhD level interns.

2. Quantum communication industry
A secondary quantum technology market that will profit by the Fellowship extension, is that of quantum communication. Gaining spatial capabilities will make quantum communication much more realistic. Specifically, we will target Cambridge Quantum Computing, who design quantum resistant secure authentication protocols, and have already expressed interest. Companies such as this will be reached by implementing prototype software tools.

3. Students
Students of quantum computer science will benefit from the Fellowship extension in several ways. Explanations of the counterintuitive nature of the subject are eased by diagrammatic rather than algebraic presentation. Supporting software tools are tangible and extremely effective to explore perplexing ideas. Specifically, BSc and MSc projects to be supervised in the Fellowship extension will train specialists for the quantum technology industry.

4. Public
The general public has a lasting fascination with fundamental questions about nature and clamours for tangible explanations. The foundational results of the Fellowship extension will be appreciated for cutting explanations down to their essence. In general such an attitude also changes one's own thinking for the better, and inspires ideas, and in this sense communication is not a one-way street. Specifically, public engagement will be achieved through participation in science festivals with hands-on presentations including interactive elements.

5. Society
In the longer term, the Fellowship extension contributes towards the trustworthiness and reliability of quantum technology. Because this emerging area will have such a disruptive societal influence, this will benefit policy makers, judges, journalists, and others who currently find it hard to gauge this new technology.