Gareth Roberts Memorial Lecture
In natural conditions photons, the particles of light, do not interact and so do not form complex forms as other particles, such as atoms or molecules, do. However, scientists are able to engineer structures in which photons are made to interact strongly leading to a unique possibility of creating objects made from light. Indeed, liquid light has been realised and showed analogous phenomena to what one can observe with water in oceans such as waves, vortices and turbulent flows. Most recently crystals of light have been produced, and effort is now under way to construct configurations analogous to real materials. There are many advantages to being in the light world: the very small mass of photons causes quantum weirdness to kick in already at room temperature, and there is much less dirt and uncontrolled complexity. In this talk I will discuss how our synthetic light world can be realised, used to simulate and help to understand complex phenomena in real materials, and find its applications in quantum technology.