Transport of ultracold atoms in superpositions of S- and D-band states in a moving optical lattice

Abstract

The ultracold atoms in a moving optical lattice with its high controllability is a feasible platform to research the transport phenomenon. Here, we study the transport process of ultracold atoms at the D band in a one-dimensional optical lattice, and perform the manipulation of atomic transport by modulating the population proportion of S band and D band. In the experiment, we first load ultracold atoms into the optical lattice using shortcut method, and then accelerate the optical lattice by scanning the phase of lattice beams. The atomic transport in D band and S band is demonstrated respectively. We find the group velocity of atoms in D band is opposite to that in S band. By doping atoms of D band into that of S band, group velocity of the atomic superposition state is modulated, and the manipulation of atomic group velocity from positive to negative is realized. Furthermore, the influence of lattice depth and acceleration on the transport distance are studied. The calculations with multi-orbital simulation are coincident with the experimental results. Our work provides a useful method to manipulate the atomic transport in higher or mixed orbits.