Notes on a surface defect in the O(N) model

Simone Giombi, Bowei Liu

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


We study a surface defect in the free and critical O(N) vector models, defined by adding a quadratic perturbation localized on a two-dimensional subspace of the d-dimensional CFT. We compute the beta function for the corresponding defect renormalization group (RG) flow, and provide evidence that at long distances the system flows to a nontrivial defect conformal field theory (DCFT). We use epsilon and large N expansions to compute several physical quantities in the DCFT, finding agreement across different expansion methods. We also compute the defect free energy, and check consistency with the so-called b-theorem for RG flows on surface defects.

Original languageEnglish (US)
Article number4
JournalJournal of High Energy Physics
Issue number12
StatePublished - Dec 2023

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics


  • Renormalization Group
  • Scale and Conformal Symmetries


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