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arXiv · 2305.11402

Notes on a Surface Defect in the $O(N)$ Model

Simone Giombi·Bowei Liu
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Abstract

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.

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Simone Giombi, Bowei Liu. 2023-05-19. Notes on a Surface Defect in the $O(N)$ Model. https://doi.org/10.1007/jhep12(2023)004

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