Research: Weyl semimetals provide new perspective on effect from high-energy physics

Weyl semimetals are characterized by topologically stable nodal points in their energy spectrum that give rise to quantum anomalies such as the chiral anomaly known from relativistic field theory. Remarkably, the recent realization of Weyl semimetals in condensed matter systems allows for the experimental observation of such subtle quantum effects in table top experiments. Here, the effect of long-ranged interactions on Weyl semimetals is studied. With an exactly solvable model, such interactions are shown to be capable of giving rise to unpaired Weyl nodes, a situation that is fundamentally forbidden to occur in non-interacting systems. Adding a magnetic field, the robustness of the chiral anomaly even in this extreme scenario is demonstrated, and the natural question how the protected Fermi-arc surface states of the Weyl semimetal are affected by long-ranged interactions is addressed.

T. Meng, J. C. Budich,
Unpaired Weyl Nodes from Long-Ranged Interactions: Fate of Quantum Anomalies,
Phys. Rev. Lett. 122, 04602 (2019)