Effects of disorder on atomic density waves and spin-singlet dimers in one-dimensional optical lattices

TL;DR

This study uses density-functional theory to analyze how disorder affects atomic density waves and spin-singlet dimers in a one-dimensional attractive Hubbard model, revealing their sensitivity and instability under disorder.

Contribution

It provides a detailed analysis of disorder effects on density waves and dimers in a 1D Hubbard model using Bethe-ansatz density-functional theory, considering strong correlations.

Findings

Atomic density waves are sensitive to disorder.

Spin-singlet dimers are unstable against disorder.

Weak disorder suppresses spin-singlet pairs.

Abstract

Using the Bethe-ansatz density-functional theory, we study a one-dimensional Hubbard model of confined attractively interacting fermions in the presence of a uniformly distributed disorder. The strongly-correlated Luther-Emery nature of the attractive one-dimensional Hubbard model is fully taken into account as the reference system in the density-functional theory. The effects of the disorder are investigated on the atomic-density waves in the weak-to-intermediate attractive interaction and on the spin-singlet dimers of doubly occupied sites in the strongly attractive regime. It is found that atomic density waves are sensitive to the disorder and the spin-singlet dimers of doubly occupied sites are quite unstable against the disorder. We also show that very weak disorder could smear the singularities in the stiffness, thus suppress the spin-singlet pairs.