Orateur
Description
Near-extremal black holes with an AdS2 throat are of great interest in
string theory and in holography due to their ubiquity as classical
gravitational saddles. The emergent SL(2,R) symmetry associated to the
throat plays an important role in their low-temperature physics. In this
talk, I will describe recent progress on analytically computing
holographic correlators in black hole spacetimes with a near-extremal
AdS2xR2 near-horizon geometry, focusing on current-current and shear
correlators. By improving on previous matching calculations, I will show
how it is possible to obtain analytical approximations to the
correlators that interpolate between the hydrodynamic (frequencies small
compared to the temperature) and the non-hydrodynamic low-temperature
regimes. The expressions we obtain capture the hydrodynamic poles, the
gapped poles controlled by the SL(2,R) symmetry of the AdS2 throat and
the successive collisions with them. I will also comment on the
appearance of zero temperature gapless poles in the spectrum and their
relation to the SL(2,R) spectrum.