Author: mehulmalik

How do you measure large quantum superpositions of time?

Measuring a time-bin qubit (d=2) normally requires an unbalanced (Franson) interferometer that coherently combines an early and late time-bin. Extending this to high-dimensional (d>2) time-bin quDits is very difficult, usually requiring multiple, bulky, phase-stabilized interferometers that are difficult to align.

In our latest preprint, we show how a high-dimensional time-bin quDit (d=11) can be measured by harnessing space-time coupling in a multi-mode fibre. We use wavefront shaping in space to program large, multi-mode unbalanced (Franson) interferometers for time inside the fiber!

arXiv link: https://arxiv.org/abs/2601.14565

We are currently advertising two 4-year PhD studentships on entanglement generation and distribution. These positions are funded by the European Research Council, the UK Engineering and Physical Sciences Research Council, and the BT Group (via an Industrial Doctoral Landscape Award).

If you are interested in joining us, please have a look at our Openings page for more information. The positions will be open to applications until Feb 15th, 2026.

I am very pleased to share that I have been awarded a Consolidator Grant from the European Research Council (ERC). The €3M QUEST project will harness the enormous potential of structured quantum light in space and time to develop new quantum technologies for the efficient generation, distribution, and measurement of entanglement. We will be advertising PhD and Postdoc positions associated with this grant soon. Please register your interest on our openings page if you would like to be notified when these positions are open.

Heriot-Watt press release: https://www.hw.ac.uk/news/2025/major-european-grant-boosts-quantum-research-at-heriot-watt-university
ERC press release: https://erc.europa.eu/news-events/news/erc-2025-consolidator-grants-results

A big welcome to Samuel Donachie, who joins us for his PhD from Paris, France! Samuel obtained his Masters in Physics from La Sorbonne University in Paris, during which he was with us for a summer internship back in 2024. Samuel is part of the new Applied Quantum Technologies Centre for Doctoral Training (CDT) hosted at Heriot-Watt, Glasgow, and Strathclyde Universities. He is currently working on designing large-scale quantum circuits for structured light. Interestingly, Samuel is also the first (half) Scottish member of our group! Here’s to many exciting years of quantum research ahead 🙂

Someone recently asked me what I was most proud of this year. Without a doubt, it was the two incredible PhDs who graduated from my research group at Heriot-Watt University! Dr Suraj Goel successfully defended his thesis on “Quantum Optical Circuits with Structured Light” and Dr Sophie Engineer, a University of Bristol QET Labs CDT student, successfully defended her thesis on “Characterising Quantum Phenomena: Entanglement, Channels and Measurement.”

A huge congratulations to you both!!