High-Dimensional Quantum Technologies: Harnessing Structured Light for the Quantum Networks of Tomorrow

High-dimensional quantum states of light structured in space and time offer significant potential for enhancing quantum technologies. Also known as “qudits,” such states can carry significantly more information than conventional qubits, enabling noise-robust and high-capacity quantum communication networks. The ability to precisely control and measure photonic qudits is a central challenge in this field.

In this webinar hosted by the Quantum Computing Technical Group, Mehul Malik will demonstrate how one can harness complex scattering processes to program arbitrary quantum circuits and measurements for photonic qudits encoded in space and time. First, he will present a “top-down” approach where a smaller unitary transformation is embedded inside the larger modal space of a complex medium, with the auxiliary modes serving as an additional resource. Prof. Malik will show how this capability allows one to engineer generalized photonic circuits inside a commercial multi-mode fiber and use them for realizing a large-scale, reconfigurable quantum network of eight users that achieves flexible entanglement routing and swapping. Next, he will discuss how spatio-temporal coupling inside a multi-mode fiber can be harnessed to program generalized projective measurements for high-dimensional photonic time-bins.

Finally, he will show how these techniques can be used to coherently excite, collect, and process single-photons from up to five quantum dots on a single sample, demonstrating effects such as cooperative emission and multi-photon interference.

Subject Matter Level: Intermediate - Assumes basic knowledge of the topic

What You Will Learn:
• Encoding and controlling high-dimensional quantum states of light
• Unitary operations using complex media
• Using multi-mode optical fiber as a platform for linear optical circuits

Who Should Attend:
PhD students, Postdocs and Academics working in the areas of:
• Photonic quantum technologies
• Quantum communications
• High-dimensional quantum states

About the Presenter: Mehul Malik from Heriot-Watt University

Mehul Malik is an Optica Fellow, Professor of Physics, and Royal Academy of Engineering Chair in Emerging Technologies at Heriot-Watt University, Edinburgh, where he leads the Beyond Binary Quantum Information research group (https://bbqlab.org/). His research focuses on the study of structured quantum light in space and time, and its application in quantum technologies for communication, computing, and sensing. Mehul’s work includes the creation of the first three-particle entanglement in high dimensions and the unprecedented transport of entanglement through a complex medium. Mehul’s research contributions have been recognised by the 2021 Royal Society of Edinburgh Early Career Medal and as a 2024 UK Blavatnik Awards Finalist. He has been awarded an ERC Starting grant, an EPSRC Early Career Fellowship, and a Marie-Sklowdowska Curie Fellowship. He is a co-Investigator in two UK National Quantum Technology Hubs on Networks (IQN) and Sensing (QuSIT) and an Associate Editor for Optica.