Reflection and Transmission for Conformal Defects

TL;DR

This paper introduces measures of reflectivity and transmissivity for conformal defects in field theories, providing explicit calculations for various models including the Ising model and minimal models, enhancing understanding of defect properties.

Contribution

It defines new quantitative measures for conformal defects and computes them explicitly in key models, advancing the analysis of defect behavior in conformal field theories.

Findings

Complete characterization of defect properties in the Ising model.

Explicit computation of defect measures in minimal models.

Analysis of defects with enhanced symmetry via coset construction.

Abstract

We consider conformal defects joining two conformal field theories along a line. We define two new quantities associated to such defects in terms of expectation values of the stress tensors and we propose them as measures of the reflectivity and transmissivity of the defect. Their properties are investigated and they are computed in a number of examples. We obtain a complete answer for all defects in the Ising model and between certain pairs of minimal models. In the case of two conformal field theories with an enhanced symmetry we restrict ourselves to non-trivial defects that can be obtained by a coset construction.