Quantum theory of asymptotically flat spacetimes

A quantum theory of asymptotically flat space-times is presented using the solutions of the Null Surface Formulation (NSF) field equations in a perturbative scheme. Free-field commutation relations are given for the null free data of NSF at future or past null infinity, and the main variables of NSF are then used to define the interior points of the space-time as labels and the metric of the space-time as a derived quantum operator. A non-trivial scattering of gravitons is given.