Conformal defects and Goldstone bosons in Anti-de Sitter space

Lorenzo Bianchi; Elia de Sabbata; Marco Meineri

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arXiv · 2605.13947

Conformal defects and Goldstone bosons in Anti-de Sitter space

Lorenzo Bianchi·Elia de Sabbata·Marco Meineri

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Abstract

We study local quantum field theories in Anti-de Sitter (AdS) space, with boundary conditions that break some of the bulk isometries. Specifically, we focus on conformal defects and we prove that their spectrum supports a displacement operator of protected dimension, despite the non-local nature of the conformal theory living at the boundary of AdS. If the defect breaks a global symmetry, a tilt operator is also present. The existence of a displacement was conjectured in arXiv:2508.08250 for Wilson loops in Yang-Mills theories in AdS. Our proof is valid in general and applies, in particular, to defects in long-range models, as we discuss in various examples. In the bulk, the modes sourced by the protected operators have Compton wavelength of order of the AdS radius: they constitute the AdS analogue of the Goldstone bosons for the spontaneous breaking of the corresponding symmetries.

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Lorenzo Bianchi, Elia de Sabbata, Marco Meineri. 2026-05-13. Conformal defects and Goldstone bosons in Anti-de Sitter space. https://arxiv.org/abs/2605.13947

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