English

Flat bands of periodic graphs

Mathematical Physics 2023-04-28 v2 math.MP Spectral Theory

Abstract

We study flat bands of periodic graphs in a Euclidean space. These are infinitely degenerate eigenvalues of the corresponding adjacency matrix, with eigenvectors of compact support. We provide some optimal recipes to generate desired bands, some sufficient conditions for a graph to have flat bands, we characterize the set of flat bands whose eigenvectors occupy a single cell and we compute the list of such bands for small cells. We next discuss stability and rarity of flat bands in special cases. Additional folklore results are proved and many questions are still open.

Keywords

Cite

@article{arxiv.2304.06465,
  title  = {Flat bands of periodic graphs},
  author = {Mostafa Sabri and Pierre Youssef},
  journal= {arXiv preprint arXiv:2304.06465},
  year   = {2023}
}

Comments

26 pages, 19 figures

R2 v1 2026-06-28T10:04:21.640Z