The Return of good, old fashioned String Theory?

Despite their close proximity, String Theory greybeards Ed Witten and Juan Maldacena virtually never publish together. Before this past week, there was only one other known paper (with Andy Strominger), Black Hole Entropy in M-Theory. So when they both are furiously involved in a single work, it's going to be good.

The topic? Black Hole entropy, of course. This time they studied it through a possible explicit relation to String Theory. Maldacena is famous for his work on the so-called AdS/CFT correspondence, which has been used to study these ideas ad nauseam. Witten has studied the black hole entropy problem from very a different perspective, and famously barked down a certain presentation using D-brane techniques to skirt strong coupling issues way back in Strings 2010.

It seems Witten's concerns may have been valid. In the present work, the authors find an technical obstruction to connecting a stringy gravitational solution to a standard, black hole solution in the Type II case. In any case, its fun to see folks worrying about fluxes, duality chasing, winding modes and the Hagedorn temperature again after all these years.