Anti-de-Sitter D-branes

TL;DR

This paper investigates various D-branes in the SL(2,R) WZW model, classifying their types, analyzing their physical viability, and exploring supersymmetric configurations relevant to stringy black holes.

Contribution

It classifies D-branes in the SL(2,R) WZW model, identifies unphysical branes, and constructs supersymmetric AdS2×S2 branes with potential black hole applications.

Findings

dS2 branes are unphysical due to supercritical electric fields

Constructed supersymmetric AdS2×S2 three-branes

Discussed differences between induced and effective geometries

Abstract

We study D-branes of the ${SL(2,\bR)}$ WZW model, and of its discrete orbifolds. Gluing the currents by group automorphisms leads to three types of D-branes: two-dimensional hyperbolic planes ($H_2$), de Sitter branes (dS$_2$), or anti-de-Sitter branes (AdS$_2$). We explain that the dS$_2$ branes are unphysical, because the electric field on their worldvolume is supercritical. By combining ${SL(2,\bR)}$ and SU(2), we exhibit a class of supersymmetric AdS$_2\times S^2$ three-brane worldvolumes, and consider their possible embeddings in the near-horizon region of stringy black holes. We point out the intriguing difference between the induced and the effective geometries of these D-branes, and speculate on its possible significance.