Giant Rydberg Excitons for Quantum Technologies

A single microwave particle of light, carrying quantum information, needs to be converted into an optical signal without scrambling the fragile quantum state it holds. This project tackles a core engineering problem for future quantum networks: quantum information degrades quickly if transmitted as microwaves, but optical signals can travel long distances through standard fibre-optic cables. The challenge is building a converter that performs this translation efficiently while preserving the quantum state. The researcher will use Rydberg excitons—highly excited, hydrogen-like particles inside a crystal of cuprous oxide—to bridge the gap between microwave and optical frequencies. If successful, this work could provide a practical building block for distributed quantum networks. Such networks would allow quantum computers in different locations to share information securely, much like today’s classical internet but with fundamentally unbreakable encryption. The immediate impact is on fundamental science: understanding how to couple Rydberg excitons to superconducting circuits. This is early-stage, curiosity-driven research. Past work on excitons and quantum optics has led to advances in sensors and secure communications, but a practical quantum converter remains years away.