Effective Field Theory Approach to Gravitationally Induced Decoherence
  Adopting the viewpoint that the standard perturbative quantization of general relativity provides an effective description of quantum gravity that is valid at ordinary energies, we show that gravity as an environment induces the rapid decoherence of stationary matter superposition states when the energy differences in the superposition exceed the Planck energy scale. 
M. P. Blencowe
quant-ph cond-mat.mes-hall gr-qc