Fuzzball geometries and higher derivative corrections for extremal holes

TL;DR

This work tackles the black hole information paradox by analyzing fuzzball geometries for extremal holes, first in the well-studied 2-charge D1-D5 system and then in the 3-charge D1-D5-P/D1-D5-KK setups. By comparing gravity travel times to dual CFT expectations, it shows that the actual geometries end in caps rather than horizons, and that for generic microstates the travel-time scale matches the CFT predictions. It also analyzes higher derivative corrections, arguing that winding-mode induced R^2 terms remain bounded and do not generate horizons, thus preserving the capped fuzzball picture. Altogether, the results support a robust fuzzball description of extremal holes and clarify how stringy corrections interact with horizonless microstate geometries, with implications for black hole interiors and information retrieval in quantum gravity.

Abstract

2-charge D1-D5 microstates are described by geometries which end in `caps' near r=0; these caps reflect infalling quanta back in finite time. We estimate the travel time for 3-charge geometries in 4-D, and find agreement with the dual CFT. This agreement supports a picture of `caps' for 3-charge geometries. We argue that higher derivative corrections to such geometries arise from string winding modes. We then observe that the `capped' geometries have no noncontractible circles, so these corrections remain bounded everywhere and cannot create a horizon or singularity.

Figures (1)

• Figure 1: (a) A graviton is incident on the component string; (b) The graviton is absorbed at A and converted to a pair of vibration modes; (c) The vibration modes meet again at B.