Broken global symmetries and defect conformal manifolds

Just as exactly marginal operators allow to deform a conformal field theory along the space of theories known as the conformal manifold, appropriate operators on conformal defects allow for deformations of the defects. When a defect breaks a global symmetry, there is a contact term in the conservation equation with an exactly marginal defect operator. The resulting defect conformal manifold is the symmetry breaking coset and its Zamolodchikov metric is expressed as the 2-point function of the exactly marginal operator. As the Riemann tensor on the conformal manifold can be expressed as an integrated 4-point function of the marginal operators, we find an exact relation to the curvature of the coset space. We confirm this relation against previously obtained 4-point functions for insertions into the 1/2 BPS Wilson loop in ${\cal N} = 4$ SYM and 3d ${\cal N} = 6$ theory and the 1/2 BPS surface operator of the 6d ${\cal N} = (2, 0)$ theory.Comment: v1: 19 pages; v2: Scope of paper broadened a bit and title changed to reflect that. Added the case of ABJM and shortened to 7 pages (2-column). Version to appear in PR