Weyl-point teleportation

Abstract

In this work, we describe the phenomenon of Weyl-point teleportation. Weyl points usually move continuously in the configuration parameter space of a quantum system when the control parameters are varied continuously. However, there are special transition points in the control space where the continuous motion of the Weyl points is disrupted. In such transition points, an extended nodal structure (nodal line or nodal surface) emerges, serving as a wormhole for the Weyl points, allowing their teleportation in the configuration space. A characteristic side effect of the teleportation is that the motional susceptibility of the Weyl point diverges in the vicinity of the transition point, and this divergence is characterized by a universal scaling law. We exemplify these effects via a two-spin model and a Weyl Josephson circuit model. We expect that these effects generalize to many other settings including electronic band structures of topological semimetals.

Birth Quota of Non-Generic Degeneracy Points

“…Our results are not exclusive to Weyl points in three dimensions (3D), we also obtain an analogous result for two-dimensional (2D) crystals with chiral symmetry illustrated on the example of bilayer graphene, as well as a minimal example in 1D. Even though we showcase the power of these results on electronic band structures of solids, they are more generic, applicable to quantum systems controlled by external parameters, such as interacting spin systems [7][8][9][10][11] or quantum circuits [12,13].…”