English

{\guillemotleft}Anticommuting{\guillemotright} $\mathbb{Z}_2$ quantum spin liquids

Strongly Correlated Electrons 2026-02-20 v2 Statistical Mechanics

Abstract

We discuss a class of lattice S=12S=\frac{1}{2} quantum Hamiltonians with bond-dependent Ising couplings and a mutually {\guillemotleft}anticommuting{\guillemotright} algebra of extensively many local Z2\mathbb{Z}_2 conserved charges that was explicated in [arXiv:2407.06236]. This mutual algebra is reminiscent of the spin-12\frac{1}{2} Pauli matrix algebra but encoded in the structure of \emph{local conserved charges}. These models have finite residual entropy density in the ground state with a simple but non-trivial degeneracy counting and concomitant quantum spin liquidity as proved in [arXiv:2407.06236]. The spin liquidity relies on a geometrically site-interlinked character of the local conserved Z2\mathbb{Z}_2 charges that is rather natural in presence of an {\guillemotleft}anticommuting{\guillemotright} structure, as opposed to for example the bond-interlinked character of the local conserved Z2\mathbb{Z}_2 hexagonal plaquette charges of the Kitaev honeycomb spin-12\frac{1}{2} model which leads to a mutually commuting local algebra. In this work, we make several exact statements on the many-body order that can be present within the class of {\guillemotleft}anticommuting{\guillemotright} quantum spin liquids. We elucidate the differences between the many-body order in these models and that found in some gapped quantum spin liquids with mutually commuting local algebras, e.g. the Kitaev toric code or Levin-Wen models. We also point out a mutually commuting algebra with local support that are naturally expressed as multi-linear Majorana forms in the Kitaev representation of these quantum spin liquids. They capture non-trivial quantum resonances throughout the lattice in these {\guillemotleft}anticommuting{\guillemotright} Z2\mathbb{Z}_2 quantum spin liquid Hamiltonians.

Keywords

Cite

@article{arxiv.2506.03866,
  title  = {{\guillemotleft}Anticommuting{\guillemotright} $\mathbb{Z}_2$ quantum spin liquids},
  author = {Sumiran Pujari and Harsh Nigam},
  journal= {arXiv preprint arXiv:2506.03866},
  year   = {2026}
}

Comments

24 pages, 15 figures. Additional elaboration in Sec. IV-C on comparison with Ising gauge theories. An additional point in Sec. II connecting the local multilinear Majorana form symmetries to a physical global Z2 symmetry. Results from previous version unaffected. A few references added following recent communication. Comments welcome