English

The AKLT model on a hexagonal chain is gapped

Quantum Physics 2020-01-08 v1 Statistical Mechanics Strongly Correlated Electrons Mathematical Physics math.MP

Abstract

In 1987, Affleck, Kennedy, Lieb, and Tasaki introduced the AKLT spin chain and proved that it has a spectral gap above the ground state. Their concurrent conjecture that the two-dimensional AKLT model on the hexagonal lattice is also gapped remains open. In this paper, we show that the AKLT Hamiltonian restricted to an arbitrarily long chain of hexagons is gapped. The argument is based on explicitly verifying a finite-size criterion which is tailor-made for the system at hand. We also discuss generalizations of the method to the full hexagonal lattice.

Cite

@article{arxiv.1904.01043,
  title  = {The AKLT model on a hexagonal chain is gapped},
  author = {Marius Lemm and Anders Sandvik and Sibin Yang},
  journal= {arXiv preprint arXiv:1904.01043},
  year   = {2020}
}

Comments

17 pages; 4 figures; 2 tables -- comments welcome

R2 v1 2026-06-23T08:25:55.610Z