"Observation of topological transitions in interacting quantum circuits"

The discovery of topological phases in condensed matter systems has changed the modern conception of phases of matter. Due to the non-local nature of ordering in these phases, direct experimental probing remains an outstanding challenge. In light of Feynman's idea of quantum simulation, we utilize superconducting qubits to investigate otherwise experimentally inaccessible topological states, and construct phase diagrams for fundamental classes of topological transitions. By designing a tunably-coupled qubit architecture and implementing a novel dynamical method, we observe an interaction-induced topological transition. Furthermore, we are able to empirically visualize the spin texture of phases and their local evolution across the transition for the Haldane model of topological states, tasks whose experimental realizations have remained elusive. Our work demonstrates that controllable quantum systems are a new platform for studying topological phases of matter and their transitions.