(2+1)d lattice models and tensor networks for gapped phases with categorical symmetry

Journal article

Gapped phases in 2+1 dimensional quantum field theories with fusion 2-categorical symmetries were recently classified and characterized using the Symmetry Topological Field Theory (SymTFT) approach [L. Bhardwaj et al., SciPost Phys. 19, 056 (2025); L. Bhardwaj et al., arXiv: 2502.20440]. In this paper, we provide a systematic lattice model construction for all such gapped phases. Specifically, we consider “all-boson type” fusion 2-category symmetries, all of which are obtainable from 0-form symmetry groups G G (possibly with an ’t Hooft anomaly) via generalized gauging—that is, by stacking with an H H -symmetric TFT and gauging a subgroup H H . The continuum classification directly informs the lattice data, such as the generalized gauging that determines the symmetry category, and the data that specifies the gapped phase. We construct commuting projector Hamiltonians and ground states applicable to any non-chiral gapped phase with such symmetries. We also describe the ground states in terms of tensor networks. In light of the length of the paper, we include a self-contained summary section presenting the main results and examples.

Authors: Inamura, K; Huang, S-J; Tiwari, A; Schäfer-Nameki, S

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: SciPost
• Journal: SciPost Physics
• Volume: 20
• Issue: 2
• Article number: 043
• Publication date: 2026-02-13
• Acceptance date: 2026-01-09
• DOI: 10.21468/scipostphys.20.2.043
• EISSN: 2542-4653
• ISSN: 2542-4653
• Language: English
• Keywords: Categorical variable; Lattice (music); Homogeneous space; Tensor (intrinsic definition); Symmetry group; Symmetry (geometry); Tensor product; Projector