Probing the quantum state of a guided atom laser pulse.
We describe bichromatic superradiant pump-probe spectroscopy as a tomographic probe of the Wigner function of a dispersing particle beam. We employed this technique to characterize the quantum state of an ultracold atomic beam, derived from a 87Rb Bose-Einstein condensate, as it propagated in a 2.5 mm diameter circular waveguide. Our measurements place an upper bound on the longitudinal phase space area occupied by the 3 x 10(5) atom beam of 9(1)Planck's constant and a lower bound on the coherence length of L>or=13(1) microm. These results are consistent with full quantum degeneracy after multiple orbits around the waveguide.
Moore
Kevin L
KL
Department of Physics, University of California, Berkeley, California 94720, USA. klmoore@berkeley.edu
Gupta
Subhadeep
S
Murch
Kater W
KW
Stamper-Kurn
Dan M
DM