Anomalous charge pumping in a one-dimensional optical superlattice

TL;DR

This paper investigates topological charge pumping in a one-dimensional optical superlattice, analyzing atomic motion and band structure to identify optimal conditions and anomalous behaviors for experimental observation.

Contribution

It provides an analytical study of band-structure evolution and atomic motion in a sliding superlattice, highlighting anomalous regimes and their implications for topological charge pumping.

Findings

Identification of optimal parameters for experimental observation

Analysis of Wannier state evolution during lattice movement

Discovery of anomalous atomic motion opposite to lattice movement

Abstract

We model atomic motion in a sliding superlattice potential to explore topological "charge pumping" and to find optimal parameters for experimental observation of this phenomenon. We analytically study the band-structure, finding how the Wannier states evolve as two sinusoidal lattices are moved relative to one-another, and relate this evolution to the center of mass motion of an atomic cloud. We pay particular attention to counterintuitive or anomalous regimes, such as when the atomic motion is opposite to that of the lattice.