Schwinger-Dyson = Wheeler-DeWitt: gauge theory observables as bulk   operators
  We argue that the second-order gauge-invariant Schwinger-Dyson operator of a gauge theory is the Wheeler-DeWitt operator in the dual string theory. Using this identification, we construct a set of operators in the gauge theory that correspond to excitations of gravity in the bulk. We show that these gauge theory operators have the expected properties for describing the semiclassical local gravity theory. 
Gilad Lifschytz and Vipul Periwal