Two-dimensional Bose-Einstein condensate in an optical surface trap

TL;DR

This paper demonstrates the creation of a two-dimensional Bose-Einstein condensate of cesium atoms in a gravito-optical surface trap, showing energies below vibrational quanta and confirming condensate presence through collapse and expansion measurements.

Contribution

It reports the first realization of a 2D Bose-Einstein condensate in an optical surface trap using cesium atoms with novel cooling and detection methods.

Findings

Condensate achieved a few micrometers above a dielectric surface.

Vertical motion energies are below vibrational quantum levels.

Condensate confirmed by collapse and expansion observations.

Abstract

We report on the creation of a two-dimensional Bose-Einstein condensate of cesium atoms in a gravito-optical surface trap. The condensate is produced a few micrometer above a dielectric surface on an evanescent-wave atom mirror. After evaporative cooling by all-optical means, expansion measurements for the tightly confined vertical motion show energies well below the vibrational energy quantum. The presence of a condensate is observed in two independent ways by a magnetically induced collapse at negative scattering length and by measurements of the horizontal expansion.