Dimensional reduction in Bose-Einstein condensed clouds of atoms confined in tight potentials of any geometry and any interaction strength

TL;DR

This paper presents a general method to reduce the three-dimensional Gross-Pitaevskii equation for Bose-Einstein condensates in tight, complex geometries to an effective one-dimensional form, accurately capturing interactions and curvature effects.

Contribution

The authors develop a variational approach to derive an effective 1D equation from the 3D Gross-Pitaevskii equation for atoms in arbitrary geometries and interaction strengths, including curvature effects.

Findings

The effective 1D model accurately reproduces the 3D solutions.

The model effectively accounts for interactions and curvature.

Application to rotating atoms in toroidal traps demonstrates its utility.

Abstract

Motivated by numerous experiments on Bose-Einstein condensed atoms which have been performed in tight trapping potentials of various geometries (elongated and/or toroidal/annular), we develop a general method which allows us to reduce the corresponding three-dimensional Gross-Pitaevskii equation for the order parameter into an effectively one-dimensional equation, taking into account the interactions (i.e., treating the width of the transverse profile variationally) and the curvature of the trapping potential. As an application of our model we consider atoms which rotate in a toroidal trapping potential. We evaluate the state of lowest energy for a fixed value of the angular momentum within various approximations of the effectively one-dimensional model and compare our results with the full solution of the three-dimensional problem, thus getting evidence for the accuracy of our model.