We present a 1d lattice model that mimics the boundary of the conventional 2d quantum spin-Hall insulator (QSHI) with U(1) symmetry and time-reversal T, satisfying T2=(−1)F. Our construction utilizes a local tensor product Hilbert space of finite site dimension with a non-onsite symmetry action. We discuss how several signature properties of the QSHI, such as the fractional charge on T-domain walls and Kramers parity switching upon π-flux threading, are manifested in our treatment. We also present a 1d Hamiltonian whose ground state realizes the conventional Luttinger-liquid phase of the QSHI edge.
@article{arxiv.1908.08958,
title = {A 1d lattice model for the boundary of the quantum spin-Hall insulator},
author = {Max A. Metlitski},
journal= {arXiv preprint arXiv:1908.08958},
year = {2019}
}