Bi-chromatic adiabatic shells for atom interferometry

Abstract

Free space atom-interferometry traditionally suffers from the large distances that atoms have to fall in order to achieve long interaction times. Trapped atom interferometry is emerging as a powerful way of achieving long interaction times in a reduced experimental volume. Here, we demonstrate bi-chromatic adiabatic magnetic shell traps as a novel tool for matterwave interferometry. We dress the magnetic hyperfine states of the F = 1 and F = 2 Rubidium 87 Bose–Einstein Condensates thus creating two independently controllable shell traps of which we use the $| F=1,{\bar{m}}_{F}=-1\rangle $ and $| F=2,{\bar{m}}_{F}=1\rangle $ adiabatic states. Using microwave pulses, we put atoms originally loaded into one of the two shell-traps into a superposition between the two shell traps. Since the two traps can be manipulated independently, their position and vertical curvature can be matched, thus creating a good starting point for an atom interferometer. This interferometer can be sensitive to spatially varying electric or magnetic fields, which could be DC or RF magnetic fields or microwaves. We demonstrate that the trap-matching afforded by the independent control of the shell traps allows for a tenfold increase in coherence times when compared to adiabatic potentials created by a single RF-frequency. For large-radius shells the atoms are confined to a 2D surface enabling highly sensitive imaging matterwave interferometers.

Keywords

• Bose–Einstein condensation
• adiabatic potentials
• matterwave interferometry
• dressed potentials
• trapped atom interferometry
• state-dependent traps