# A group theoretical route to deterministic Weyl points in chiral photonic lattices

## TL;DR

This paper demonstrates the existence of symmetry-induced, deterministic Weyl points with non-trivial topology in chiral cubic photonic systems, using group theory and physical realizations like nano plasmonic and photonic crystal structures.

## Contribution

It introduces a group theoretical approach to identify deterministic Weyl points in chiral photonic lattices, moving beyond accidental degeneracies.

## Key findings

- Existence of symmetry-induced Weyl points at Brillouin zone center
- Realization of these points in nano plasmonic and photonic crystal systems
- Topologically non-trivial dispersion with hyper-conic features

## Abstract

Classical topological phases derived from point degeneracies in photonic bandstructures show intriguing and unique behaviour. Previously identified exceptional points are based on accidental degeneracies and subject to engineering on a case-by-case basis. Here we show that symmetry induced (deterministic) pseudo Weyl points with non-trivial topology and hyper-conic dispersion exist at the centre of the Brillouin zone of chiral cubic systems. We establish the physical implications by means of a $P2_13$ sphere packing, realised as a nano plasmonic system and a photonic crystal.