Background Independent Quantum Field Theory and the Cosmological   Constant Problem
  We introduce the notion of background independent quantum field theory. The distinguishing feature of this theory is that the dynamics can be formulated without recourse to a background metric structure. We show in a simple model how the metric properties of spacetime can be recovered from the dynamics. Background independence is not only conceptually desirable but allows for the resolution of a problem haunting ordinary quantum field theory: the cosmological constant problem. 
Olaf Dreyer