BBQ Lab

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’re very excited to welcome two new PhD students to the BBQ lab!

Bilal joins us from Lahore, Pakistan. He first discovered his passion for quantum optics during his undergraduate studies, where he worked with PhysLab at LUMS — an experience that sparked his enthusiasm for the exciting research we do.

Pravalika, originally from Chennai, India, completed her Integrated MSc in Physics at the Central University of Tamil Nadu. Driven by a deep and growing interest in quantum optics, she pursued an M.Tech in Quantum Technology at IIST, Thiruvananthapuram before joining us.

We’re delighted to have both Bilal and Pravalika as part of our team and look forward to the creativity and insight they will bring to our lab. Learn more about their backgrounds and journeys before BBQ Lab on our People page.

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

What will the quantum networks of the future look like? How do you route and teleport entanglement to multiple users in a reconfigurable manner?

In our paper published in Nature Photonics this month, we show how light scattering inside a simple optical fibre can be harnessed to program complex multi-mode optical circuits. We then use these circuits to implement a completely reconfigurable quantum network interconnecting eight users with entanglement!

Looking sharp in the lab

Paper link: https://www.nature.com/articles/s41566-025-01806-x
Press release: https://www.hw.ac.uk/news/2025/shop-bought-cable-powers-quantum-breakthrough-2
Physics World Story: https://physicsworld.com/a/quantum-photonics-network-passes-a-scaling-up-milestone/