Manipulation of an elongated internal Josephson junction of bosonic atoms

TL;DR

This paper experimentally investigates a spatially extended Bose-Einstein condensate Josephson junction, confirming the applicability of local density approximation and introducing a method to produce states with uniform magnetization.

Contribution

It provides the first experimental characterization of an elongated internal Josephson junction in a BEC and demonstrates a new method to generate uniformly magnetized states.

Findings

Non-linear parameter measured with three protocols

Results consistent with local density approximation

Method developed for uniform magnetization states

Abstract

We report on the experimental characterization of a spatially extended Josephson junction realized with a coherently-coupled two-spin-component Bose-Einstein condensate. The cloud is trapped in an elongated potential such that that transverse spin excitations are frozen. We extract the non-linear parameter with three different manipulation protocols. The outcomes are all consistent with a simple local density approximation of the spin hydrodynamics, i.e., of the so-called Bose-Josephson junction equations. We also identify a method to produce states with a well defined uniform magnetization.