On the gravity dual of the light-front vacuum
  Building on a previous conjecture, we argue that the holographic dual of the light-front vacuum state of a superconformal field theory quantized in the front form of dynamics contains the Kaigorodov spacetime, which is nothing but a pp-wave propagating in AdS. Evidence in favor of this conjecture is presented. In particular we verify the matching of global symmetries and discuss the contribution of the zero mode sector in both sides of the correspondence. 
Blai Garolera
hep-th