On the quantization of the Null-Surface formulation of GR
  We define and discuss various quantum operators that describe the geometry of spacetime in quantum general relativity. These are obtained by combining the Null-Surface Formulation of general relativity, recently developed, with asymptotic quantization. One of the operators defined describes a ``fuzzy'' quantum light cone structure. Others, denoted ``spacetime-point operators'', characterize geometrically-defined physical points. We discuss the interpretation of these operators. This seems to suggest a picture of quantum spacetime as made of ``fuzzy'' physical points. We derive the commutation algebra of the quantum spacetime point operators in the linearization around flat space. 
Simonetta Frittelli, Carlos N. Kozameh, Ezra T. Newman, Carlo Rovelli,   Ranjeet S. Tate (University of Pittsburgh)