Quantum Transport of Bosonic Cold Atoms in Double Well Optical Lattices

TL;DR

This paper numerically investigates quantum transport of ultra-cold bosonic atoms in double well optical lattices, revealing quantized transport phenomena dependent on interactions and filling factors, with potential applications in atomtronics.

Contribution

It introduces a numerical study of bosonic atom transport in optical lattices under slow modulation, highlighting quantized transport and interaction effects, with a semiclassical model to explain the results.

Findings

Transport is independent of the rate of parameter change for slow modulations.

Quantized transport occurs at half filling in the strongly interacting regime.

Transport depends on atom filling and interaction strength, with fermion-like behavior at strong interactions.

Abstract

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