Modified Villain lattice realizations of flat-gauged interfaces and T-duality defects in the 2D compact boson are constructed at arbitrary radii, yielding non-compact edge modes with continuous spectrum and infinite quantum dimension.
Non-invertible defects on the worldsheet
6 Pith papers cite this work, alongside 10 external citations. Polarity classification is still indexing.
abstract
We consider codimension-one defects in the theory of $d$ compact scalars on a two-dimensional worldsheet, acting linearly by mixing the scalars and their duals. By requiring that the defects are topological, we find that they correspond to a non-Abelian zero-form symmetry acting on the fields as elements of $\text{O}(d;\mathbb{R}) \times \text{O}(d;\mathbb{R})$, and on momentum and winding charges as elements of $\text{O}(d,d;\mathbb{R})$. When the latter action is rational, we prove that it can be realized by combining gauging of non-anomalous discrete subgroups of the momentum and winding $\text{U}(1)$ symmetries, and elements of the $\text{O}(d,d;\mathbb{Z})$ duality group, such that the couplings of the theory are left invariant. Generically, these defects map local operators into non-genuine operators attached to lines, thus corresponding to a non-invertible symmetry. We confirm our results within a Lagrangian description of the non-invertible topological defects associated to the $\text{O}(d,d;\mathbb{Q})$ action on charges, giving a natural explanation of the rationality conditions. Finally, we apply our findings to toroidal compactifications of bosonic string theory. In the simplest non-trivial case, we discuss the selection rules of these non-invertible symmetries, verifying explicitly that they are satisfied on a worldsheet of higher genus.
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Introduces the twisted Villain model to realize exact T-duality on the lattice for fibred manifolds, recovering bundle-flux exchange and defining topological defects via half-gauging.
Z_k symmetries from Pythagorean triples in two free Weyl fermions yield non-invertible defects that generate all U(1)^2-preserving boundaries for two Dirac fermions.
Wess–Zumino coupling of the compactified M2-brane forces its monopole 0-form and winding 1-form symmetries into a 2-group whose Postnikov class is the mixed quantized flux.
Hodge loci in Calabi-Yau sigma models are identified with non-trivial categories of topological defects preserving N=(2,2) SCA and invertible on spectral-flow generators, with CM structure at special points.
Imposing a duality-inspired fusion rule that forbids the [ε] sector from appearing in the [ε] × [ε] OPE yields numerical bounds on (Δ_σ, Δ_ε) that include the 2d Ising model but exclude the 3d Ising model.
citing papers explorer
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Lattice Realizations of Flat Gauging and T-duality Defects at Any Radius
Modified Villain lattice realizations of flat-gauged interfaces and T-duality defects in the 2D compact boson are constructed at arbitrary radii, yielding non-compact edge modes with continuous spectrum and infinite quantum dimension.
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Stringy T-duality on the lattice and the twisted Villain model
Introduces the twisted Villain model to realize exact T-duality on the lattice for fibred manifolds, recovering bundle-flux exchange and defining topological defects via half-gauging.
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Non-Invertible Symmetries and Boundaries for Two-Dimensional Fermions
Z_k symmetries from Pythagorean triples in two free Weyl fermions yield non-invertible defects that generate all U(1)^2-preserving boundaries for two Dirac fermions.
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2-Group global symmetry in the compactified M2-brane
Wess–Zumino coupling of the compactified M2-brane forces its monopole 0-form and winding 1-form symmetries into a 2-group whose Postnikov class is the mixed quantized flux.
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Hodge Loci and Complex Multiplication via Generalized Symmetries in Calabi-Yau sigma models
Hodge loci in Calabi-Yau sigma models are identified with non-trivial categories of topological defects preserving N=(2,2) SCA and invertible on spectral-flow generators, with CM structure at special points.
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Conformal Bootstrap with Duality-Inspired Fusion Rule
Imposing a duality-inspired fusion rule that forbids the [ε] sector from appearing in the [ε] × [ε] OPE yields numerical bounds on (Δ_σ, Δ_ε) that include the 2d Ising model but exclude the 3d Ising model.