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Rotating Black Holes in AdS, Extremality and Chaos

Avik Banerjee, Arnab Kundu, Rohan R. Poojary

TL;DR

This work investigates extremal chaos in rotating AdS black holes by combining (i) near-horizon JT gravity analysis to capture thermal modes and their Schwarzian-driven OTOC growth, and (ii) probe-string worldsheet dynamics to access chaos in the dual CFT. It finds that, at extremality, chaos splits into two channels: thermal modes yielding λL = 2π T_H away from extremality and vanishing at extremality, and extremal (left-moving) AdS3 PBH modes yielding λL = 2r_+ that persist at extremality; in higher dimensions, the extremal chaos becomes a nontrivial function of the Frolov-Thorne temperatures. The results connect BTZ boundary analysis with throat dynamics, and extend the Kerr/CFT perspective to extremal chaos in AdS4, supported by worldsheet temperature calculations that reveal a consistent left-moving sector controlling the growth. Overall, the paper provides a two-pronged framework to understand scrambling at extremality and outlines the interplay between thermal and extremal modes as a route to extremal chaos in holographic CFTs.

Abstract

Extremal black holes have vanishing Hawking temperatures. In this article, we argue that for asymptotically AdS black holes, at extremality, a particular class of correlators in the dual CFT can exhibit exponential, maximally chaotic growth with a non-vanishing temperature. Our approach, at extremality, is two-fold. First, we geometrically investigate the modes that are responsible for chaos. Secondly, we study the dynamics of a probe string to capture chaos in worldsheet correlators. For rotating BTZ at extremality, the corresponding Lyapunov exponent is determined by the left-moving temperature. In higher dimensional AdS-Kerr geometries, on the other hand, the corresponding Lyapunov exponent becomes a non-trivial function of the Frolov-Thorne temperatures.

Rotating Black Holes in AdS, Extremality and Chaos

TL;DR

This work investigates extremal chaos in rotating AdS black holes by combining (i) near-horizon JT gravity analysis to capture thermal modes and their Schwarzian-driven OTOC growth, and (ii) probe-string worldsheet dynamics to access chaos in the dual CFT. It finds that, at extremality, chaos splits into two channels: thermal modes yielding λL = 2π T_H away from extremality and vanishing at extremality, and extremal (left-moving) AdS3 PBH modes yielding λL = 2r_+ that persist at extremality; in higher dimensions, the extremal chaos becomes a nontrivial function of the Frolov-Thorne temperatures. The results connect BTZ boundary analysis with throat dynamics, and extend the Kerr/CFT perspective to extremal chaos in AdS4, supported by worldsheet temperature calculations that reveal a consistent left-moving sector controlling the growth. Overall, the paper provides a two-pronged framework to understand scrambling at extremality and outlines the interplay between thermal and extremal modes as a route to extremal chaos in holographic CFTs.

Abstract

Extremal black holes have vanishing Hawking temperatures. In this article, we argue that for asymptotically AdS black holes, at extremality, a particular class of correlators in the dual CFT can exhibit exponential, maximally chaotic growth with a non-vanishing temperature. Our approach, at extremality, is two-fold. First, we geometrically investigate the modes that are responsible for chaos. Secondly, we study the dynamics of a probe string to capture chaos in worldsheet correlators. For rotating BTZ at extremality, the corresponding Lyapunov exponent is determined by the left-moving temperature. In higher dimensional AdS-Kerr geometries, on the other hand, the corresponding Lyapunov exponent becomes a non-trivial function of the Frolov-Thorne temperatures.

Paper Structure

This paper contains 15 sections, 112 equations, 1 figure.

Figures (1)

  • Figure 1: We have plotted the worldsheet temperature, in units of the Frolov-Thorne temperature $T_{FT}$, defined in eqn (\ref{['Kerr_ext_temp']}). Here curves corresponds to setting $r_0 = 1/2, 2/5, 1/3$, from top to bottom, respectively. Clearly, the curves end at $|\omega|=1$, which is the causality bound.