Half-BPS Janus solutions in AdS$_7$

TL;DR

This paper constructs and analyzes half-BPS flow solutions in 7d supergravity with AdS$_3$ slices, exploring their uplifts to 11d and IIA supergravity, and interprets them as defect CFT$_2$ within 6d SCFTs, including central charge calculations.

Contribution

It introduces a novel analytic method for solving BPS equations in 7d supergravity and characterizes smooth, asymptotically AdS$_7$ solutions with AdS$_3$ slices, including their uplifts and holographic duals.

Findings

Constructed smooth half-BPS solutions with AdS$_3$ slices in 7d supergravity.

Uplifted solutions describe deformations of AdS$_7$ vacua in M-theory and IIA supergravity.

Computed holographic central charges for the dual defect CFT$_2$.

Abstract

We study half-BPS flows in gauged minimal 7d supergravity featured by an AdS$_3\times S^3$ slicing of the metric, supported by a dyonic three-form field. We first present a novel strategy for analytic integration of the BPS equations, which makes use of the integrals of motion. Subsequently, we discuss the suitable choice of integration constants that gives rise to smooth geometries. These flows are asymptotically locally AdS$_7$ in their UV limit, while their IR geometry is AdS$_3\times \mathbb{R}^4$. We then discuss their uplifts to 11d and massive IIA supergravity and observe that they describe one-parameter deformations of their AdS$_7\times S^4$ and AdS$_7\times S^3$ vacua, respectively, their holographic interpretation being as conformal defect CFT$_2$'s within the corresponding dual SCFT$_6$'s. We conclude with the computation of the holographic central charge, by focussing on the M-theory interpretation.