Moulting Black Holes (SUSY and non SUSY)

We first find a family of novel supersymmetric phases of the D1-D5
CFT, which in certain ranges of charges have more entropy than all
known ensembles. We also find bulk BPS configurations that exist in
the same range of parameters as these phases, and have more entropy
than a BMPV black hole; they can be thought of as coming from a BMPV
black hole shedding a “hair” condensate outside of the horizon. The
entropy of the bulk configurations is smaller than that of the CFT
phases, which indicates that some of the CFT states are lifted at
strong coupling. Neither the bulk nor the boundary phases are captured
by the elliptic genus, which makes the coincidence of the phase
boundaries particularly remarkable. Our configurations are the first
instance of a black hole entropy enigma with a controlled CFT
dual. Furthermore, contrary to common lore, these objects exist in a
region of parameter space (between the ``cosmic censorship bound'' and
the ``unitarity bound'') where no black holes were thought to exist.

Motivated by this we expect stable bound states of non-extremal
rotating three-charge black holes in five dimensions (Cvetic-Youm
black holes) and super tubes. We study the system in the probe limit
and find that generically the susy marginal bound state becomes
metastable and disappears with non-extremality. However near
extremality our expectation is realized and there are stable bound
states. Angular momentum repulsion is mainly responsible for this
effect. We use this setup in the D1-D5 decoupling limit to map a
thermodynamic instability of the CFT (from BH phase to new phase) to a
dynamical instability of BH to the supertube-BH bound state.