Correlated bosons in a one-dimensional optical lattice: Effects of the trapping potential and of quasiperiodic disorder

TL;DR

This study explores how trapping potentials and quasiperiodic disorder influence the quantum phases of strongly correlated ultracold bosons in one-dimensional optical lattices, revealing new disordered phases.

Contribution

It introduces a meanfield approach to analyze the impact of trapping and quasiperiodic disorder on quantum phases in 1D bosonic systems, highlighting the emergence of a metastable-disordered phase.

Findings

Small atom number leads to Mott-insulating phase unaffected by trap variation.

Quasiperiodic potential induces a metastable-disordered phase.

Disordered phase is neither compressible nor Mott insulating.

Abstract

We investigate the effect of the trapping potential on the quantum phases of strongly correlated ultracold bosons in one-dimensional periodic and quasiperiodic optical lattices. By means of a decoupling meanfield approach, we characterize the ground state of the system and its behavior under variation of the harmonic trapping, as a function of the total number of atoms. For a small atom number the system shows an incompressible Mott-insulating phase, as the size of the cloud remains unaffected when the trapping potential is varied. When the quasiperiodic potential is added the system develops a metastable-disordered phase which is neither compressible nor Mott insulating. This state is characteristic of quasidisorder in the presence of a strong trapping potential.