Probing the Berry Curvature and Fermi Arcs of a Weyl Circuit

TL;DR

This paper demonstrates a topological circuit that exhibits Weyl dispersion, revealing Weyl points, Fermi arcs, Berry curvature, and chiral charge, enabling advanced studies of topological physics in engineered systems.

Contribution

It introduces a 3D circuit platform that models Weyl physics, providing full access to spin-texture, Berry curvature, and topological features in a controllable setting.

Findings

Observation of Weyl points and Fermi arcs

Mapping of Berry curvature distribution

Quantification of Weyl point chiral charge

Abstract

The Weyl particle is the massless fermionic cousin of the photon. While no fundamental Weyl particles have been identified, they arise in condensed matter and meta-material systems, where their spinor nature imposes topological constraints on low-energy dispersion and surface properties. Here we demonstrate a topological circuit with Weyl dispersion at low-momentum, realizing a 3D lattice that behaves as a half-flux Hofstadter model in all principal planes. The circuit platform provides access to the complete complex-valued spin-texture of all bulk- and surface- states, thereby revealing not only the presence of Weyl points and the Fermi arcs that connect their surface-projections, but also, for the first time, the Berry curvature distribution through the Brillouin zone and the associated quantized Chiral charge of the Weyl points. This work opens a path to exploration of interacting Weyl physics in superconducting circuits, as well as studies of how manifold topology impacts band topology in three dimensions.