Instability of Black Holes in AdS$_3 \times S^3$

TL;DR

This paper investigates the instability of extremal and near extremal black holes in AdS3×S3, analyzing their parameter space, decay processes, and constructing classical string solutions to understand their decay products.

Contribution

It provides a detailed analysis of black hole instability regions, decay mechanisms via dual CFT2 response functions, and introduces new classical string solutions as potential decay products.

Findings

Instability regions are characterized by specific parameter bounds.

Decay onset matches thermodynamic predictions.

New classical string solutions called 'giants' are constructed.

Abstract

Extremal and near extremal black holes are unstable, unless they are protected by supersymmetry. For black holes in AdS$_3 \times S^3$, we study the range of parameters that bound the unstable region, the fate of extremal black holes that are unstable, and the true ground state in super-selection sectors where no isolated black hole solution exists. Thermodynamics generally favors a central black hole surrounded by chiral primaries that carry a significant fraction of the conserved charges. We give a dynamical interpretation of decay, by computing the linear response functions in the dual CFT$_2$ and showing that the onset of instability agrees with thermodynamics. To understand the nature of the decay products, we construct several new families of classical string solutions. They are ``giants" that move on both the AdS$_3$ and the $S^3$, and may have interesting applications beyond those we develop.