Higher dimensional holography
The holographic dictionary is well developed for gravity in asymptotically anti de Sitter $A(AdS_{d+1})$ spacetimes. However, this approach is limited, since many physically relevant configurations, such as bubbling geometries dual to heavy operators, do not arise as an uplift of a lower dimensional $A(AdS_{d+1})$ solution. Instead, they are intrinsic solutions of ten- or eleven-dimensional supergravity. In this work, we address this problem by evaluating the on-shell Type IIB supergravity action, with a suitable boundary counterterm, on the bubbling solutions describing half-BPS surface operators in $\mathcal{N}=4$ super Yang-Mills. This calculation exactly reproduces the surface operator Euler conformal anomaly, an observable known exactly in the field theory but previously inaccessible holographically. This example illustrates the need for a higher-dimensional approach to holographic renormalization applicable to general asymptotically $AdS_{d+1} \times M_q$ geometries.