For gapped 1D U(1)-symmetric systems, every ground state satisfies ⟨U_F⟩=1+O(1/L) for topologically trivial twisting operators, so a violation proves gaplessness.
Title resolution pending
1 Pith paper cite this work. Polarity classification is still indexing.
1
Pith paper citing it
fields
cond-mat.str-el 1years
2026 1verdicts
CONDITIONAL 1representative citing papers
citing papers explorer
-
Gaplessness indicator by topologically trivial twisting operators
For gapped 1D U(1)-symmetric systems, every ground state satisfies ⟨U_F⟩=1+O(1/L) for topologically trivial twisting operators, so a violation proves gaplessness.