Interaction versus dimerization in one-dimensional Fermi systems

TL;DR

This study investigates how interaction and lattice distortion influence quantum coherence in one-dimensional Fermi systems, revealing the conditions under which delocalized or dimerized phases occur based on interaction type and lattice modifications.

Contribution

It combines numerical DMRG and analytical bosonization to analyze the effects of interaction and dimerization on phase behavior in 1D Fermi systems, highlighting the role of lattice modifications.

Findings

Delocalized phase exists for attractive interactions.

Dimerized ground state occurs for repulsive interactions with lattice effects.

Dimerization is suppressed at half filling due to large correlation gap.

Abstract

In order to study the effect of interaction and lattice distortion on quantum coherence in one-dimensional Fermi systems, we calculate the ground state energy and the phase sensitivity of a ring of interacting spinless fermions on a dimerized lattice. Our numerical DMRG (Density Matrix Renormalization Group) studies, in which we keep up to 1000 states for systems of about 100 sites, are supplemented by analytical considerations using bosonization techniques. We find a delocalized phase for an attractive interaction, which differs from that obtained for random lattice distortions. The extension of this delocalized phase depends strongly on the dimerization induced modification of the interaction. Taking into account the harmonic lattice energy, we find a dimerized ground state for a repulsive interaction only. The dimerization is suppressed at half filling, when the correlation gap becomes large.