Quantum transport of bosonic cold atoms in double-well optical lattices

Abstract

We numerically investigate, using the time evolving block decimation\nalgorithm, the quantum transport of ultra-cold bosonic atoms in a double well\noptical lattice through slow and periodic modulation of the lattice parameters\n(intra- and inter-well tunneling, chemical potential, etc.). The transport of\natoms does not depend on the rate of change of the parameters (as along as the\nchange is slow) and can distribute atoms in optical lattices at the quantized\nlevel without involving external forces. The transport of atoms depends on the\natom filling in each double well and the interaction between atoms. In the\nstrongly interacting region, the bosonic atoms share the same transport\nproperties as non-interacting fermions with quantized transport at the half\nfilling and no atom transport at the integer filling. In the weakly interacting\nregion, the number of the transported atoms is proportional to the atom\nfilling. We show the signature of the quantum transport from the momentum\ndistribution of atoms that can measured in the time of flight image. A\nsemiclassical transport model is developed to explain the numerically observed\ntransport of bosonic atoms in the non-interacting and strongly interacting\nlimits. The scheme may serve as an quantized battery for atomtronics\napplications.\n