Monodromy Defects from Hyperbolic Space

Abstract

We study monodromy defects in $O(N)$ symmetric scalar field theories in $d$ dimensions. After a Weyl transformation, a monodromy defect may be described by placing the theory on $S^1\times H^{d-1}$, where $H^{d-1}$ is the hyperbolic space, and imposing on the fundamental fields a twisted periodicity condition along $S^1$. In this description, the codimension two defect lies at the boundary of $H^{d-1}$. We first study the general monodromy defect in the free field theory, and then develop the large $N$ expansion of the defect in the interacting theory, focusing for simplicity on the case of $N$ complex fields with a one-parameter monodromy condition. We also use the $\epsilon$-expansion in $d=4-\epsilon$, providing a check on the large $N$ approach. When the defect has spherical geometry, its expectation value is a meaningful quantity, and it may be obtained by computing the free energy of the twisted theory on $S^1\times H^{d-1}$. It was conjectured that the logarithm of the defect expectation value, suitably multiplied by a dimension dependent sine factor, should decrease under a defect RG flow. We check this conjecture in our examples, both in the free and interacting case, by considering a defect RG flow that corresponds to imposing alternate boundary conditions on one of the low-lying Kaluza-Klein modes on $H^{d-1}$. We also show that, adapting standard techniques from the AdS/CFT literature, the $S^1\times H^{d-1}$ setup is well suited to the calculation of the defect CFT data, and we discuss various examples, including one-point functions of bulk operators, scaling dimensions of defect operators, and four-point functions of operator insertions on the defect.

64 pages, 8 figures, v2: Typos corrected, references added, enhanced discussion in section 4

References in corpus (7)

• Towards a derivation of holographic entanglement entropy
• Entanglement Entropy in the O(N) model
• Twist operators in higher dimensions
• Charged Renyi entropies and holographic superconductors
• Hovering Black Holes from Charged Defects
• Free energy and defect $C$-theorem in free scalar theory
• The $\epsilon$-expansion of the codimension two twist defect from conformal field theory

Cited by in corpus (12)

• Selected Topics in Analytic Conformal Bootstrap: A Guided Journey
• Localized magnetic field in the $O(N)$ model
• Spin Impurities, Wilson Lines and Semiclassics
• Bootstrapping boundary-localized interactions II: Minimal models at the boundary
• Weyl Anomalies of Four Dimensional Conformal Boundaries and Defects
• Analytic bootstrap for the localized magnetic field
• A dispersion relation for defect CFT
• Phases of Wilson Lines in Conformal Field Theories
• Bootstrapping Monodromy Defects in the Wess-Zumino Model
• RG flows on two-dimensional spherical defects
• Interacting conformal scalar in a wedge
• Shape Deformations of Charged Rényi Entropies from Holography