S-folds and holographic RG flows on the D3-brane

Abstract: Type IIB S-folds of the form $\,\textrm{AdS}{4} \times \textrm{S}^1 \times \textrm{S}^5\,$ are conjectured to correspond to new strongly coupled three-dimensional CFT's on a localised interface of $\,\textrm{SYM}{4}\,$. In this work we construct holographic RG flows on the D3-brane that generically connect anisotropic deformations of $\,\textrm{SYM}{4}\,$ in the UV to various S-fold $\textrm{CFT}$'s in the IR with different amounts of supersymmetry and flavour symmetries. Examples of holographic RG flows between \mbox{S-fold} CFT's are also presented. Lastly a geometric interpretation of axion deformations is provided in terms of monodromies on the internal $\,\textrm{S}^{5}\,$ when moving around the $\,\textrm{S}^{1}$. Special attention is paid to the monodromy-induced patterns of symmetry breaking as classified by the mapping torus $T{h}(\textrm{S}^5)$.