Trapped Electrons and Ions Join Forces to Detect Single Photons

In this high-risk-high-gain project on a boundary between applied and fundamental sciences, we propose to develop and test a radio-frequency signal detection scheme utilising free electrons as the detectors and laser-cooled ions as the means of the information read-out. Containing the quantum mechanically coupled system of laser-cooled ions and electrons in a unique ion trap, a highly efficient and tuneable detector that can detect single photons of electromagnetic radiation will be realised. The device is initialised by itself, requiring no special state preparation steps, making it highly robust and simple. The information will be read out using a fibre-based optical cavity. In the long term, we aim to investigate how the coupling of electron and ion quantum systems can be exploited for obtaining additional signal information such as phase and propagation direction. This project will synergise young theoreticians and experimentalists and significantly advance our understanding of the unique quantum system not realised in the world so far.