  In loop quantum gravity, matter fields can have support only on the
`polymer-like' excitations of quantum geometry, and their algebras of
observables and Hilbert spaces of states can not refer to a classical,
background geometry. Therefore, to adequately handle the matter sector, one has
to address two issues already at the kinematic level. First, one has to
construct the appropriate background independent operator algebras and Hilbert
spaces. Second, to make contact with low energy physics, one has to relate this
`polymer description' of matter fields to the standard Fock description in
Minkowski space. While this task has been completed for gauge fields, important
gaps remained in the treatment of scalar fields. The purpose of this letter is
to fill these gaps.

General Relativity and Quantum Cosmology