Unitarity Method for Holographic Defects

We initiate the study of loop-level holographic correlators in the presence of defects. We present a unitarity method which constructs loop corrections from lower order data. As an example, we apply this method to 6d $\mathcal{N}=(2,0)$ theories with $\frac{1}{2}$-BPS surface defects and report the first holographic two-point function at one loop.