Boundary conformal field theory at large charge

Gabriel Cuomo, Márk Mezei, Avia Raviv-Moshe

Research output: Contribution to journalArticlepeer-review


We study operators with large internal charge in boundary conformal field theories (BCFTs) with internal symmetries. Using the state-operator correspondence and the existence of a macroscopic limit, we find a non-trivial relation between the scaling dimension of the lowest dimensional CFT and BCFT charged operators to leading order in the charge. We also construct the superfluid effective field theory for theories with boundaries and use it to systematically calculate the BCFT spectrum in a systematic expansion. We verify explicitly many of the predictions from the EFT analysis in concrete examples including the classical conformal scalar field with a |ϕ|6 interaction in three dimensions and the O(2) Wilson-Fisher model near four dimensions in the presence of boundaries. In the appendices we additionally discuss a systematic background field approach towards Ward identities in general boundary and defect conformal field theories, and clarify its relation with Noether’s theorem in perturbative theories.

Original languageEnglish
Article number143
JournalJournal of High Energy Physics
Issue number10
StatePublished - Oct 2021
Externally publishedYes


  • Boundary Quantum Field Theory
  • Conformal Field Theory
  • Effective Field Theories
  • Global Symmetries


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