Experimental study of free-space phase-based long-distance quantum key distribution

Quantum communications are revolutionising the way we transmit information and connect remote parties. Leveraging on the quantum properties of photons and on the tools developed for optical communications, it is now possible to distribute quantum coherence and confidential information to distant users, thus shaping the future quantum internet.

This emerging technology is of interest to academia and industry alike and is attracting substantial funding from governments worldwide. The U.K., in particular, has invested on quantum technologies since 2013 through the U.K. National Quantum Technologies Programme and has recently announced a new National Quantum Strategy worth £2.5 billion.

Quantum communications can be established at any scale, from a few metres to hundreds of kilometres, using optical fibres, up to thousands of kilometres with a ground-to-satellite link. However, coherently connecting users that are separated by a large distance remains an elusive target. The most promising solution to date is the phase-based protocol that came into existence in 2018 under the name of ‘Twin-Field Quantum Key Distribution’ (TF-QKD) [1]. It has the peculiarity of exploiting the phase relation between the light beams sent by distant users to create a shared key that can be used for cryptographic purposes.

In this project, you will perform experimental research on phase-based QKD protocols conceived for long-distance communications, like TF-QKD, over free-space channels, to connect buildings, flying objects and satellites. This will facilitate the future deployment of phase-based QKD systems in real quantum networks and will inform the creation of interfaces between free-space and fibre-based channels.

This project is in collaboration with the Quantum Communications Hub and the studentship is funded. The student will be primarily located at York, where equipment for optical free space links is available, but visits to relevant research centres will be considered for training purposes. The project is experimental and mainly involves device control and programming. We are seeking PhD candidates with suitable undergraduate training in physics, engineering, computer science or related subjects who are keen to research in quantum optics and its applications to communications. Priority will be given to candidates with a personal interest in the engineering aspects of the experimental work, e.g., an optical Pointing Acquisition and Tracking (PAT) system [2] for the communication link.

For informal enquiry please contact Prof. Marco Lucamarini ([Email Address Removed]).

This position will be advertised until filled.

Eligibility

UK students

3 years tuition fees plus up to 3.5 years stipend (£18,622 in 2023/24).

Academic entry requirements: at least a class 2:1 MSc or MPhys degree in Physics.