Alladi Ramakrishnan Hall

The Aretakis instability of extremal asymptotically AdS black holes

Arun Ravishankar

University of Arizona

A few years back Aretakis discovered that extremal horizons are linearly unstable to perturbations. Over the last few years more details of the story of the instability have been revealed. I will present our work that attempts to unravel some of the open questions:
* Is there a holographic signature of the Aretakis instability? We study the planar RNAdS5 black hole to answer this question.
* There are two non-overlapping/complimentary techniques to study the instability of extremal horizons - Aretakis' method using conserved charges on the horizon and the mode sum decomposition method using matched asymptotics . We study the BTZ black hole which gives us the full Green function which allows us to get more insight on the instability.