Ab-initio phase diagram of ultracold 87-Rb in an one-dimensional two-color superlattice

TL;DR

This paper maps the phase diagram of ultracold 87-Rb atoms in a one-dimensional two-color superlattice using ab-initio calculations, revealing how laser intensities control quantum phases like superfluid, Mott-insulator, and Bose-glass.

Contribution

It provides an ab-initio approach linking experimental parameters to quantum phases in a superlattice, including detailed finite-size and convergence analysis.

Findings

All relevant quantum phases are accessible via laser intensity control.

The phase diagram is significantly influenced by the longitudinal trapping potential.

The study demonstrates the effectiveness of the density-matrix renormalization-group method for such systems.

Abstract

We investigate the ab-initio phase diagram of ultracold 87-Rb atoms in an one-dimensional two-color superlattice. Using single-particle band structure calculations we map the experimental setup onto the parameters of the Bose-Hubbard model. This ab-initio ansatz allows us to express the phase diagrams in terms of the experimental control parameters, i.e., the intensities of the lasers that form the optical superlattice. In order to solve the many-body problem for experimental system sizes we adopt the density-matrix renormalization-group algorithm. A detailed study of convergence and finite-size effects for all observables is presented. Our results show that all relevant quantum phases, i.e., superfluid, Mott-insulator, and quasi Bose-glass, can be accessed through intensity variation of the lasers alone. However, it turns out that the phase diagram is strongly affected by the longitudinal trapping potential.