Condensate localization in a quasi-periodic structure

TL;DR

This paper demonstrates how a quasi-periodic Fibonacci array affects Bose-Einstein condensate transport, revealing localization effects caused by spectral minigaps, which can be observed experimentally through tunneling measurements.

Contribution

It introduces a method to realize a Fibonacci quasi-periodic potential for BECs and analyzes localization effects using a Bose-Hubbard model.

Findings

Localization effects due to spectral minigaps

Observable tunneling suppression with increased force

Potential for experimental detection of quasi-periodic localization

Abstract

We propose a set-up of optical laser beams by which one may realize a quasi-one-dimensional Fibonacci array of potential wells for a Bose-Einstein condensate. We use a Bose-Hubbard tight-binding model to evaluate the transport of superfluid Rb87 atoms driven by a constant force through such an array. We show that the minigaps that are generated in the spectral density-of-states by the quasi-periodic disorder give rise to prominent localization effects, which can be observed by measuring the tunnel output of matter into vacuum as a function of the intensity of the applied force.