  To understand how charge transport is affected by a background medium and
vice versa we study a two-channel transport model which captures this interplay
via a novel, effective fermion-boson coupling. By means of (dynamical) DMRG we
prove that this model exhibits a metal-insulator transition at half-filling,
where the metal typifies a repulsive Luttinger liquid and the insulator
constitutes a charge density wave. The quantum phase transition point is
determined consistently from the calculated photoemission spectra, the scaling
of the Luttinger liquid exponent, the charge excitation gap, and the
entanglement entropy.
