# Non-Local Annihilation of Weyl Fermions in Correlated Systems

## TL;DR

This paper demonstrates that strong electron-electron interactions can cause abrupt, non-local creation or annihilation of Weyl fermions in correlated systems, fundamentally altering the transition to Weyl semimetals.

## Contribution

It reveals that many-body correlations can induce discontinuous Weyl node transitions and affect Fermi arc properties, challenging the independent electron approximation.

## Key findings

- Weyl node pairs can appear or disappear suddenly in spectral functions.
- Transitions to Weyl semimetals can be discontinuous due to correlations.
- Electronic correlations influence Fermi arc structures.

## Abstract

Weyl semimetals (WSMs) are characterized by topologically stable pairs of nodal points in the band structure, that typically originate from splitting a degenerate Dirac point by breaking symmetries such as time reversal or inversion symmetry. Within the independent electron approximation, the transition between an insulating state and a WSM requires the local creation or annihilation of one or several pairs of Weyl nodes in reciprocal space. Here, we show that strong electron-electron interactions may qualitatively change this scenario. In particular, we reveal that the transition to a Weyl semi-metallic phase can become discontinuous, and, quite remarkably, pairs of Weyl nodes with a finite distance in momentum space suddenly appear or disappear in the spectral function. We associate this behavior to the buildup of strong many-body correlations in the topologically non-trivial regions, manifesting in dynamical fluctuations in the orbital channel. We also highlight the impact of electronic correlations on the Fermi arcs.