INTERACTION VERSUS DIMERIZATION IN ONE-DIMENSIONAL FERMI SYSTEMS

In order to study the effect of interaction and lattice distortion on quantum coherence in one-dimensional Fermi systems, we calculate the g round state energy and the phase sensitivity of a ring of interacting spinless fermions on a dimerized lattice. Our numerical DMRG studies, in which we keep up to 1000 states for systems of about 100 sites, are supplemented by analytical considerations using bosonization techniqu es. We find a delocalized phase for an attractive interaction, which d iffers from that obtained for random lattice distortions. The extensio n of this delocalized phase depends strongly on the dimerization induc ed modification of the interaction. Taking into account the harmonic l attice energy, we find a dimerized ground state for a repulsive intera ction only. The dimerization is suppressed at half filling, when the c orrelation gap becomes large.