3 papers
cond-mat.mes-hall2026
Ideal Bands in Tight-Binding Models
Lexu Zhao, Yang Ge, Shinsei Ryu +1
A band is called ideal when its Dirichlet functional saturates the topological lower bound. We study ideal bands in finite-band tight-binding models with conventional two-dimension…
cond-mat.str-el2026
Higher-Form Anomalies on Lattices
Yitao Feng, Ryohei Kobayashi, Yu-An Chen +1
Higher-form symmetry in a tensor product Hilbert space is always emergent: the symmetry generators become genuinely topological only when the Gauss law is energetically enforced at…
cond-mat.str-el2025
Higher Hall conductivity from a single wave function: Obstructions to symmetry-preserving gapped edge of (2+1)D topological order
Ryohei Kobayashi, Taige Wang, Tomohiro Soejima +2
A (2+1)D topological ordered phase with U(1) symmetry may or may not have a symmetric gapped edge state, even if both thermal and electric Hall conductivity are vanishing. It is re…