Looking for event horizons using UV/IR relations
  A primary goal in holographic theories of gravity is to study the causal structure of spacetime from the field theory point of view. This is a particularly difficult problem when the spacetime has a non-trivial causal structure, such as a black hole. We attempt to study causality through the UV/IR relation between field theory and spacetime quantities, which encodes information about bulk position. We study the UV/IR relations for charged black hole spacetimes in the AdS/CFT correspondence. We find that the UV/IR relations have a number of interesting features, but find little information about the presence of a horizon in the bulk. The scale of Wilson loops is simply related to radial position, whether there is a horizon or not. For time-dependent probes, the part of the history near the horizon only effects the late-time behaviour of field theory observables. Static supergravity probes have a finite scale size related to radial position in generic black holes, but there is an interesting logarithmic divergence as the temperature approaches zero. 
James P. Gregory and Simon F. Ross