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 3$d$ 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.