On generalised D1-D5 near horizons and their spectra

There has been considerable recent interest in type II string compactifications on AdS3×S3×M4 due to both new progress in the AdS3/CFT2 correspondence and an independent search for new N\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \mathcal{N} $$\end{document} = (4, 0) supergravity solutions. In this work we report a new family of small N\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \mathcal{N} $$\end{document} = (4, 0) preserving warped AdS3×S3×CY2 compactifications of type IIB supergravity. The S3 in this family is non trivially fibered over the CY2. We show how these new solutions provide a IIB embedding of minimal ungauged d = 5 supergravity coupled to an Abelian vector multiplet. We also make a few initial steps towards the identification of dual CFT2 candidates. Specifically, we study the Kaluza-Klein spectrum of the spin two and certain vector fluctuations that are expected to be dual to the stress-energy tensor, SU(2) R current and several other BPS operator families in the dual CFT2.