Half-Spacetime Gauging of 2-Group Symmetry in 3d
Abstract
We construct a class of non-invertible duality defects, in (2+1)d quantum field theories, arising from half-spacetime gauging of a 2-group symmetry. Starting from a parent theory with two discrete and Abelian 0-form symmetries and a prescribed mixed anomaly, we show that gauging one factor produces a theory with a 2-group symmetry, while gauging the other yields a theory with a non-invertible 0-form symmetry, whose fusion rules we derive explicitly. When the parent theory possesses three such symmetries with a cyclic anomaly structure, gauging different factors can produce mutually dual theories and the half-spacetime gauging of the 2-group is implemented by a non-invertible duality defect, whose fusion rules we obtain. We illustrate the construction with explicit examples, including a U(1)× U(1)× U(1) gauge theory and a general class of product theories. We also include a self-contained pedagogical introduction to the cohomological tools employed throughout the article.
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BibTeX
@misc{bason2026halfspacetime,
title = {{Half-Spacetime Gauging of 2-Group Symmetry in 3d}},
author = {Davide Bason and Wei Cui and Lorenzo Ruggeri},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2605.06287},
eprint = {2605.06287},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2605.06287},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Half-Spacetime Gauging of 2-Group Symmetry in 3d
AU - Davide Bason
AU - Wei Cui
AU - Lorenzo Ruggeri
PY - 2026
DA - 2026/09/13
PB - arXiv
DO - 10.48550/arxiv.2605.06287
UR - https://arxiv.org/abs/2605.06287
AB - We construct a class of non-invertible duality defects, in (2+1)d quantum field theories, arising from half-spacetime gauging of a 2-group symmetry. Starting from a parent theory with two discrete and Abelian 0-form symmetries and a prescribed mixed anomaly, we show that gauging one factor produces a theory with a 2-group symmetry, while gauging the other yields a theory with a non-invertible 0-form symmetry, whose fusion rules we derive explicitly. When the parent theory possesses three such symmetries with a cyclic anomaly structure, gauging different factors can produce mutually dual theories and the half-spacetime gauging of the 2-group is implemented by a non-invertible duality defect, whose fusion rules we obtain. We illustrate the construction with explicit examples, including a U(1)× U(1)× U(1) gauge theory and a general class of product theories. We also include a self-contained pedagogical introduction to the cohomological tools employed throughout the article.
ER -