Radio-frequency induced ground state degeneracy in a Chromium Bose-Einstein condensate

TL;DR

This paper explores how strong radio-frequency fields can induce ground state degeneracy in a chromium Bose-Einstein condensate by modifying Zeeman states, revealing new loss processes and potential for quantum control.

Contribution

It demonstrates the use of rf fields to achieve degeneracy of Zeeman states in a chromium BEC and analyzes the associated dressed state dynamics and loss mechanisms.

Findings

Rf fields can bring Zeeman states to degeneracy despite static magnetic fields.

The lifetime of rf-dressed BECs is affected by a new dipole-dipole interaction induced loss.

Adiabaticity of rf dressing influences the degeneracy and stability of the dressed states.

Abstract

We study the effect of strong radio-frequency (rf) fields on a chromium Bose-Einstein condensate (BEC), in a regime where the rf frequency is much larger than the Larmor frequency. We use the modification of the Land\'{e} factor by the rf field to bring all Zeeman states to degeneracy, despite the presence of a static magnetic field of up to 100 mG. This is demonstrated by analyzing the trajectories of the atoms under the influence of dressed magnetic potentials in the strong field regime. We investigate the problem of adiabaticity of the rf dressing process, and relate it to how close the dressed states are to degeneracy. Finally, we measure the lifetime of the rf dressed BECs, and identify a new rf-assisted two-body loss process induced by dipole-dipole interactions.