Quantum Institute: Visitor Schedule

The Quantum Lunch is regularly held on Thursdays in the Theoretical Division Conference Room, TA-3, Building 123, Room 121.
For more information, contact Diego Dalvit.

April 12, 2007
T-11 Conference Room, TA-3-524-106
2:00 PM - 3:00 PM

Changehyun Ryu,
NIST

Observation of Persistent Flow of a Bose-Einstein Condensate in a Toroidal Trap

Abstract

I will describe experiments on the generation and study of vortex states in a Bose-Einstein condensate of sodium atoms confined in an oblong, torus-shaped trap. The vortex states are created by the coherent transfer of the orbital angular momentum of a photon to an atom in quantized units of h, using a 2-photon stimulated Raman process with Laguerre-Gaussian beams. The trap is formed by the combination of an elliptically shaped, magnetic trap with a blue detuned laser beam in the middle to exclude atoms from the center of the magnetic trap. Thus, the blue detuned laser beam effectively acts as a pinning potential for the vortex generated. We have observed that the rotational flow of atoms persists for several seconds, even when the condensate fraction is less than 15%.