Probing the Berry curvature and Fermi arcs of a Weyl circuit

Topology has recently emerged as a powerful tool in condensed matter physics to engineer materials whose macroscopic properties are robust to imperfections. Indeed, rather than measuring the ``topological invariants'' associated with the band structure of a material, the existence of such invariants is often inferred from observations of disorder robustness. Here, the authors directly measure such a topological invariant by building a ``topological circuit'' that exhibits Weyl points, one of the paradigmatic topological features of 3d band structures. The exaggerated size of the unit cell in the circuit allows for measurement of the complete band structure and Berry curvature of the circuit's bands, and thus a direct measurement of the chiral charge of Weyl points.