Optical Confinement of a Bose-Einstein Condensate

Abstract

Bose-Einstein condensates of sodium atoms have been confined in an optical dipole trap using a single focused infrared laser beam. This eliminates the restrictions of magnetic traps for further studies of atom lasers and Bose-Einstein condensates. More than five million condensed atoms were transferred into the optical trap. Densities of up to $3 \times 10^{15} cm^{-3}$ of Bose condensed atoms were obtained, allowing for a measurement of the three-body decay rate constant for sodium condensates as $K_3 = (1.1 \pm 0.3) \times 10^{-30} cm^6 s^{-1}$. At lower densities, the observed 1/e lifetime was more than 10 sec. Simultaneous confinement of Bose-Einstein condensates in several hyperfine states was demonstrated.Comment: 5 pages, 4 figure

Vortices in a trapped dilute Bose-Einstein condensate

“…In oblate traps with ω z ≫ ω ⊥ , however, the spin-gauge effect can be significant (Ω s could be comparable with ω ⊥ for large enough values of ω z ). Recently, the MIT group has succeeded in trapping a 23 Na Bose condensate by purely optical means [158,159]. In contrast to a magnetic trap, the spins of the alkali atoms in such an optical trap are essentially free, so that the spinor nature of the alkali Bose condensate can be fully realized.…”

Spinor Condensates and Light Scattering from Bose-Einstein Condensates

“…In contrast, a far-off-resonant optical trap confines atoms regardless of their hyperfine state [44]. Thus, the atomic spin is liberated from the requirements of magnetic trapping and becomes a new degree of freedom.…”

“…First, magnetically-trapped Bose-Einstein condensates were produced in the |F = 1, m F = −1 hyperfine state and transferred to an optical trap [44]. Then, we pulsed on rf fields of variable strength which were swept in frequency to distribute the optically-trapped atoms among the F = 1 hyperfine sublevels by the method of adiabatic rapid passage [106].…”

“…Since the realization of an optical trap for Bose-Einstein condensates [44], our group has performed several experimental studies of this new quantum fluid. In three different experiments we explored the ground-state spin structure of spinor condensates in external magnetic fields [97], the formation and persistence of metastable spin domain configurations [98], and the transport across spin domain boundaries by quantum tunneling [99].…”

“…11). For example, Rayleigh scattering of near-resonant light from a sodium condensate at a density of 3×10 15 cm −3 , which is the maximum density of condensates which has been obtained in optical traps [44], should be reduced by a factor of two. It would also be interesting to measure this suppression of light scattering at a Feshbach resonance [45], where the chemical potential can be made quite large by tuning the scattering length a using magnetic fields.…”