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Abstract

We use the separate universe framework to study cosmological perturbations
within the group field theory formalism for quantum gravity, based on
multi-condensate quantum states. Working with a group field theory action for
gravity minimally coupled to four scalar fields that can act as a set of
relational clock and rods, we argue that these multi-condensate states
correspond to cosmological space-times with small long-wavelength scalar
perturbations. Equations of motion for the cosmological perturbations are
derived, which in the classical limit agree with the standard results of
general relativity and also include quantum gravity corrections that become
important when the space-time curvature approaches the Planck scale.