Perturbative Relationships Between QCD and Gravity and Some Implications
  We discuss nontrivial examples illustrating that perturbative gravity is in some sense the `square' of gauge theory. This statement can be made precise at tree-level using the Kawai, Lewellen and Tye relations between open and closed string tree amplitudes. These relations, when combined with modern methods for computing amplitudes, allow us to obtain loop-level relations, and thereby new supergravity loop amplitudes. The amplitudes show that N=8 supergravity is less ultraviolet divergent than previously thought. As a different application, we show that the collinear splitting amplitudes of gravity are essentially squares of the corresponding ones in QCD. 
Z. Bern, L. Dixon, D.C. Dunbar, M. Perelstein and J.S. Rozowsky