  We define bulk/boundary maps corresponding to quantum gravity states in the
tensorial group field theory formalism, for quantum geometric models sharing
the same type of quantum states of loop quantum gravity. The maps are defined
in terms of a partition of the quantum geometric data associated to an open
graph into bulk and boundary ones, in the spin representation. We determine the
general condition on the entanglement structure of the state that makes the
bulk/boundary map isometric (a necessary condition for holographic behaviour),
and we analyse different types of quantum states, identifying those that define
isometric bulk/boundary maps.
