The Experimental Quantum Information Physics Unit carries out experimental studies on highly controllable quantum systems. A particular research emphasis is put on the development of ion traps with optical interfaces mediated by single photons. A single atomic ion is trapped inside a high-Q optical micro-resonator such that it strongly interacts with photons. The unit investigates the novel physics of such strongly coupled quantum systems and harnesses the ion-photon interaction to create a functional quantum device for networked quantum information processing.