Superfluid-Mott-Insulator Transition in a One-Dimensional Optical Lattice with Double-Well Potentials

TL;DR

This paper investigates the superfluid-Mott-insulator transition in a one-dimensional optical lattice with double-well potentials, revealing complex behaviors due to quantum tunneling and interactions, using density-matrix renormalization group methods.

Contribution

It introduces a detailed analysis of phase transitions in a double-well optical lattice, highlighting novel step-plateau structures and satellite peaks related to tunneling and correlations.

Findings

Rich step-plateau structure in visibility

Satellite peaks in momentum distribution

Quantum tunneling influences phase coherence

Abstract

We study the superfluid-Mott-insulator transition of ultracold bosonic atoms in a one-dimensional optical lattice with a double-well confining trap using the density-matrix renormalization group. At low density, the system behaves similarly as two separated ones inside harmonic traps. At high density, however, interesting features appear as the consequence of the quantum tunneling between the two wells and the competition between the "superfluid" and Mott regions. They are characterized by a rich step-plateau structure in the visibility and the satellite peaks in the momentum distribution function as a function of the on-site repulsion. These novel properties shed light on the understanding of the phase coherence between two coupled condensates and the off-diagonal correlations between the two wells.