Optical photons - for all practical purposes - do not interact with each other. In fact, this fundamental property of light and other electromagnetic waves underlies all our communication technology from radio transmission to fibre-optic communication lines. More generally, our ability to generate, control and detect light has not only revolutionised modern telecommunication, but has had a broad impact on science and society, from remote sensing in meteorology and climatology, over optical tomography in biomedicine to the recent detection of gravitational waves. On the other hand, the possibility to exploit quantum mechanical phenomena such as coherence, quantum superposition and quantum entanglement of photons opens fundamentally new directions for communication and computation using light. Exploiting these novel concepts requires ability to generate and manipulate light at the level of single photons. Exploring novel approaches to generating effective interaction between individual photons thus forms the core goal of this research project.
More specifically, the project employs a combination of state-of-the-art experimental techniques from atomic physics and quantum optics, including ultracold atomic gases, strongly interacting Rydberg atoms, and coherent optical control methods such as electromagnetically induced transparency to realize an optical medium inside which individual photons behave like interacting particles. Building on this novel concept, the project explores both fundamental aspects of the quanta of light as well as technological applications in quantum information.
