Bose-Einstein condensates in rf-dressed adiabatic potentials

Bose-Einstein condensates of ${}^{87}\mathrm{Rb}$ atoms are transferred into radio-frequency induced adiabatic potentials and the properties of the corresponding dressed states are explored. We report on measurements of the spin composition of dressed condensates. We also show that adiabatic potentials can be used to trap atom gases in novel geometries, including suspending a cigar-shaped cloud above a curved sheet of atoms.

Figure 1

Adiabatic potentials for the $F=1$ state in the presence of gravity. The potential $U$ is shown along the $\widehat{\mathit{y}}$ direction for the ∣+⟩, ∣0⟩, and ∣−⟩ states on the right and with no rf magnetic field present on the left. The arrows indicate how the $m_F$ states transform when the rf field is turned on adiabatically for positive $(\Delta >0)$ and negative $(\Delta <0)$ detuning.

Figure 2

(Color online) Ratio of $m_F=0$ atoms to total number of $m_F=0$ and $m_F=-1$ atoms vs rf frequency. Data for rf frequencies greater (less) than $1.328\mathrm{MHz}$ represent atoms confined in the $U_{-}$ $\left(U_{+}\right)$ potential. Each data point represents a single image, except the points with error bars, which are each an average of seven measurements; the error bars indicate the standard deviation of these measurements. The solid line is a fit to Eq. (3). Open circles represent data points for which gravitational sag is calculated to shift the measured ratio by more than 1% and are not included in the fit. The inset shows a typical image used to obtain the data; the field of view is approximately 260 by $370\mu {\mathrm{m}}^2$. The lower (upper) cloud consists of $m_F=0$ $(m_F=-1)$ atoms.

Figure 3

(Color online) Displacement from the IP trap center for atoms trapped in $U_{+}$ potential for different rf frequencies. The solid line shows the calculated displacement. The inset shows atoms simultaneously loaded into the $U_{-}$ (upper cloud) and $U_{+}$ potentials at $\Delta =2\pi \times 1\mathrm{MHz}$. The field of view for the inset (taken while the atoms were trapped) is approximately 640 by $390\mu {\mathrm{m}}^2$.