Figure 1:
(Left) Black hole spacetimes develop a “throat” leading to the horizon. (Right) The throat viewed from above. Quantum gravitational dynamics in some black hole throats can be “holographically” encoded in the dynamics of a lower dimensional field theory defined on the boundary of the throat. The radial direction of spacetime becomes an emergent geometric description of RG scale in the field theory. Red shading on the boundary indicates the nonlocal spread of data about a local bulk object in the boundary encoding. The depth of red shading indicates the fraction of information about the bulk object that is encoded at each boundary location.