Line defects as brane boxes in Gaiotto-Maldacena geometries

We construct a new family of $\text{AdS}_2\times S^2\times S^2$ solutions to Type IIA supergravity with 4 supercharges acting with non-Abelian T-duality on the recent class constructed in arXiv:2107.12277. We focus on a particular solution in this class asymptoting locally to an $\text{AdS}_5$ Gaiotto-Maldacena geometry. This solution allows for a line defect interpretation within the 4d $\mathcal{N}=2$ SCFT dual to this geometry, that we study in detail. We show that the defect branes, consisting on a non-trivial intersection of D2-D4-NS5-F1 branes, can be interpreted as baryon vertices within the 4d $\mathcal{N}=2$ SCFT, whose backreaction gives rise to the $\text{AdS}_2$ solution. We construct the explicit quiver quantum mechanics that flows in the IR to the dual SCQM, and show that it can be embedded within the quiver CFT associated to the $\text{AdS}_5$ solution. The quiver quantum mechanics arises from a brane box set-up of D2-branes stretched between perpendicular NS5-branes, that we construct from the $\text{AdS}_2$ solution. We provide non-trivial checks of our proposed duality. Our construction provides one further example of the successful applications of non-Abelian T-duality to holography, in this case in providing a very non-trivial connection between $\text{AdS}_2$ solutions, line defects and brane boxes.