Fundamental Superstrings as Holograms

TL;DR

This paper explores the holographic relationship between fundamental superstrings and black hole horizons, constructing an exact worldsheet CFT for the near horizon region of small black strings with matching symmetries and entropy.

Contribution

It provides the first exact worldsheet CFT description of the near horizon region of small black strings, demonstrating symmetry matching and entropy agreement.

Findings

Symmetries of the hologram are reproduced from the bulk description.

The boundary Virasoro central charge matches the Wald entropy.

An exact CFT description is constructed for small black holes in string theory.

Abstract

The worldsheet of a macroscopic fundamental superstring in the Green-Schwarz light-cone gauge is viewed as a possible boundary hologram of the near horizon region of a small black string. For toroidally compactified strings, the hologram has global symmetries of AdS_3 \times S^{d-1} \times T^{8-d}, (d =3,..,8), only some of which extend to local conformal symmetries. We construct the bulk string theory in detail for the particular case of d=3. The symmetries of the hologram are correctly reproduced from this exact worldsheet description in the bulk. Moreover, the central charge of the boundary Virasoro algebra obtained from the bulk agrees with the Wald entropy of the associated small black holes. This construction provides an exact CFT description of the near horizon region of small black holes both in Type-II and heterotic string theory arising from multiply wound fundamental superstrings.