# Quantum non-local theory of topological Fermi arc plasmons in Weyl semimetals

## TL;DR

This paper develops a quantum non-local theory for Fermi arc plasmons in Weyl semimetals, revealing how topological surface states interact with bulk electrons and include quantum effects like penetration and dissipation.

## Contribution

It introduces a novel quantum-mechanical non-local framework for topological Fermi arc plasmons in Weyl semimetals, incorporating quantum penetration and dissipation effects.

## Key findings

- Quantum effects of Fermi arc penetration into bulk are significant.
- Dissipation arises mainly from bulk electron-hole pair decay processes.
- The theory captures non-local electron-electron interactions in Weyl semimetals.

## Abstract

The surface of a Weyl semimetal (WSM) displays Fermi arcs, i.e. disjoint segments of a two-dimensional Fermi contour. We present a quantum-mechanical non-local theory of chiral Fermi arc plasmons in WSMs with broken time-reversal symmetry. These are collective excitations constructed from topological Fermi arc and bulk electron states and arising from electron-electron interactions, which are treated in the realm of the random phase approximation. Our theory includes quantum effects associated with the penetration of the Fermi arc surface states into the bulk and dissipation, which is intrinsically non-local in nature and arises from decay processes mainly involving bulk electron-hole pair excitations.