Satellite Quantum Communication

The distribution of quantum states is required for quantum communication tasks such as quantum key distribution (QKD) and networking of quantum computers. Exponential losses in optical fibres restricts direct transmission to under several hundred kilometres, insufficient for intercontinental or global range, without the use of hitherto impractical quantum repeaters. Space-based quantum communication links are one method by which global quantum communication networks may be deployed.
The highly successful Chinese satellite Micius has experimentally demonstrated the basic principles in orbit but considerable challenges remain in the development of affordable and widespread space quantum communication systems. Significant global effort has been spurred by the Chinese successes, the UK has several programmes aimed at rapidly developing the knowledge and expertise required to build and deploy space quantum communication systems including the Quantum Research CubeSat project led by the University of Strathclyde
This PhD project will address the challenges of quantum space systems development by investigating the use of smallsats, CubeSats in particular, that offer much reduced development and launch costs. But the size, weight, and power constraints pose their own challenges. The project will look at optimising satellite QKD under resource constraints as well as the operation of constellations to provide wide-scale coverage. This will be conducted by analysis of QKD protocols, especially with finite-block size effects and highly varying channel loss characteristic of satellite quantum links, as well as the performance of constellation configurations to distribute quantum resources.