A DMRG study of a level coupled to a 1D interacting lead

The influence of nearest neighbor interactions in a reservoir coupled to a single level dot on the width of the level is studied, using the density matrix renormalization group (DMRG) method. We find that while in the Luttinger liquid (LL) phase of the lead (i.e., for weak interactions) the interactions cause a gradual decrease of the resonance width, in the charge density wave (CDW) phase (for strong interactions) the width is zero, and a sharp jump of the dot population occurs. We explain the physical difference between both cases.