Possibility of observing energy decoherence due to quantum gravity

The possibility of observing energy decoherence due to quantum gravity, corresponding to a discretization of time at the Planck scale, is discussed. The observable effects are governed by the relative phase between the two systems and are unchanged by energy decoherence that acts globally on system and phase reference together. It was suggested that the basic reason for the need for a phase reference is the fact that macroscopic objects have very little energy coherence. Energy decoherence acting locally below the micrometer scale is already ruled out by atom interferometer