Abstract

In physics a central question regards the nature of elementary constituents in our universe are, and how they interact. The properties of the particles that we have uncovered are closely related to, and therefore limited in their richness by, the nature of the vacuum in our universe. Over the years it has also become apparent that new and exciting vacua can be realised when a large number of particles are brought together which strongly interact: these vacua can come with new `emergent’ particles. This forces us to revisit our understanding of elementary particles, and at times to turn it on its head. The new vacua can be highly exotic in nature, with unusual correlations often described as `topological’. Their emergent particles correspondingly exhibit unprecedented properties, such as the separation of spin and charge in electronic systems; to particles that behave neither like fermions nor bosons; and finally to a long sought-after freely mobile magnetic charge. After years of a global research effort, we are gradually developing the tools to understand and control these new emergent particles, and we are ready to start exploring their enticing potential.