COHERENT SPIN DYNAMICS IN AN OPTICALLY

TRAPPED BOSE-EINSTEIN CONDENSATE

Adam Black, Eduardo Gomez, Lincoln Turner, Sebastian Jung, and Paul Lett

National Institute of Standards & Technology, Atomic Physics Division

100 Bureau Drive, Stop 8424, Gaithersburg, MD 20899-8424, USA

While collisions in a thermal gas are often thought of as random, incoherent events, in a Bose-Einstein condensate (BEC) the coherent nature of collisions becomes clear. We make use of an optically trapped sodium BEC of spin one to explore equilibria and dynamics in a system allowing spin-changing collisions.

In a first set of experiments, we experimentally find the ground-state spin populations of the spinor condensate as a function of magnetic field and magnetization. We find that this phase diagram is characteristic of antiferromagnetic spin interactions. This agrees with theoretical predictions and prior observations of the scattering properties of the spin-one ground state in sodium.

We then perturb the spin state of the atoms away from this equilibrium state, and find that the spin populations can be made to oscillate for as much as hundreds of milliseconds. Measurements of the period and amplitude of oscillation agree with theoretical predictions, and indicate that we approach a regime of highly nonlinear spin dynamics.

Category: Physics

Name:                      Adam Black

Mentor's name:        Paul Lett

Division:                  Atomic Physics Division (842)

Laboratory:              Laser Cooling and Trapping Group

Address:                   Rm. B241, Bldg. 216, Stop 8424

Telephone #:           (301) 975-2353

FAX #:                     (301) 975-8272

email:                       adam.black@nist.gov

Not a Sigma Xi member

Name:                      Eduardo Gomez

Mentor's name:        Paul Lett

Division:                  Atomic Physics Division (842)

Laboratory:              Laser Cooling and Trapping Group

Address:                   Rm. B257, Bldg. 216, Stop 8424

Telephone #:            (301) 975-4414

FAX #:                      (301) 975-8272

email:                       eduargo.gomez@nist.gov

Not a Sigma Xi member

Name:                      Lincoln Turner

Mentor's name:        Paul Lett

Division:                  Atomic Physics Division (842)

Laboratory:              Laser Cooling and Trapping Group

Address:                   Rm. B141, Bldg. 216, Stop 8424

Telephone #:           (301) 975-6882

FAX #:                      (301) 975-8272

email:                       lincoln.turner@nist.gov

Not a Sigma Xi member

Name:                      Sebastian Jung

Mentor's name:        Paul Lett

Division:                  Atomic Physics Division (842)

Laboratory:              Laser Cooling and Trapping Group

Address:                   Rm. B241, Bldg. 216, Stop 8424

Telephone #:           (301) 975-2576

FAX #:                     (301) 975-8272

email:                       sebastian.jung@nist.gov

Not a Sigma Xi member