On supersymmetric AdS3 solutions of Type II

We classify supersymmetric warped AdS3×wM7 backgrounds of Type IIA and Type IIB supergravity with non-constant dilaton, generic RR fluxes and magnetic NSNS flux, in terms of a dynamic SU(3)-structure on M7. We illustrate our results by recovering several solutions with various amounts of supersymmetry. The dynamic SU(3)-structure includes a G2-structure as a limiting case, and we show that in Type IIB this is integrable.

New non-perturbative de Sitter vacua in α′-complete cosmology

The α′-complete cosmology developed by Hohm and Zwiebach classifies the O(d, d; ℝ) invariant theories involving metric, b-field and dilaton that only depend on time, to all orders in α′. Some of these theories feature non-perturbative isotropic de Sitter vacua in the string frame, generated by the infinite number of higher-derivatives of O(d, d; ℝ) multiplets. Extending the isotropic ansatz, we construct stable and unstable non-perturbative de Sitter solutions in the string and Einstein frames. The generalized equations of motion admit new solutions, including anisotropic d + 1-dimensional metrics and non-vanishing b-field. In particular, we find dSn+1× Td−n geometries with constant dilaton, and also metrics with bounded scale factors in the spatial dimensions with non-trivial b-field. We discuss the stability and non-perturbative character of the solutions, as well as possible applications.

BLACK HOLES IN THE PRESENCE OF COSMOLOGICAL CONSTANT AND LARGE-N BRANE WORLD

Gravitational theories including negative cosmological constant, dilaton and gauge fields are explored in higher dimensions, in which black hole solutions are shown to exist and their asymptotic behaviors are obtained. Based on these solutions, effective Randall–Sundrum brane worlds are constructed. In the framework of gauge/gravity duality, effects from cosmological constant on the spectra of standard model fields on the branes are perturbatively calculated.