Sodium Bose-Einstein Condensates in the F=2 State in a Large-volume Optical Trap

TL;DR

This paper reports the creation and stability of sodium Bose-Einstein condensates in the F=2 hyperfine state within a large-volume optical trap, and measures density-dependent frequency shifts of specific transitions.

Contribution

It demonstrates the formation of stable sodium BECs in the F=2 state using microwave transitions and characterizes their properties in a large optical trap.

Findings

Condensates in the F=2, m_F=-2 state are stable for several seconds.

Density-dependent frequency shift of the clock transition measured as (2.44±0.25)×10^{-12} Hz·cm^3.

Successful creation of sodium BECs in a high-field seeking state in a large-volume optical trap.

Abstract

We have investigated the properties of Bose-Einstein condensates of sodium atoms in the upper hyperfine ground state in a purely optical trap. Condensates in the high-field seeking $| F=2, m_F=-2>$ state were created from initially prepared $| F=1,m_F=-1>$ condensates using a one-photon microwave transition at 1.77 GHz. The condensates were stored in a large-volume optical trap created by a single laser beam with an elliptical focus. We found condensates in the stretched state $| F=2, m_F=-2>$ to be stable for several seconds at densities in the range of $10^{14}$ atoms/cm$^{3}$. In addition, we studied the clock transition $| F=1, m_F=0>$ $\to$ $| F=2, m_F=0>$ in a sodium Bose-Einstein condensate and determined a density-dependent frequency shift of $(2.44\pm 0.25) \times 10^{-12}$ Hz cm$^{3}$.