Ab initio phase diagram of ultracold 87Rb in a one-dimensional two-colour superlattice

Felix Schmitt (1) , Markus Hild (1) , Robert S. Roth (1)

1 Institut für Kernphysik

We investigate the ab-initio phase diagram of ultracold 87 Rb atoms in an onedimensional 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 manybody problem for experimental system sizes we adopt the density-matrix renormalizationgroup algorithm. A detailed study of convergence and finite-size e ffects 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. Ab initio phase diagram of ultracold 87 Rb in a one-dimensional two-color superlattice 2

Mots clés: 67.85.Hj; 03.75.Lm; 67.85.-d

Felix Schmitt, Markus Hild, Robert S. Roth. Ab initio phase diagram of ultracold 87Rb in a one-dimensional two-colour superlattice. Journal of Physics B: Atomic, Molecular and Optical Physics, 2010, 43 (23), pp.235301. ⟨10.1088/0953-4075/43/23/235301⟩. ⟨hal-00576261⟩