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Unformatted text preview: re then
imaged by resonant absorption imaging (Fig. 1). Bragg
scattered atoms were distinguished from the unscattered
atoms by their axial displacement. The speed of Bogoliubov sound at the center of the trapped condensate
is related to the velocity of radial expansion yr as cs
11 mm s at m h
6.7 kHz as shown
yr 2  (cs
in Fig. 1). Thus, by comparing the axial displacement of
the scattered atoms to the radial extent of the expanded
FIG. 2. Bragg scattering of phonons and of free particle
condensate, one sees that the Bragg scattering recoil veMomentum transfer per particle, in units of hq, is shown
locity is smaller than the speed of sound in the trapped
the frequency difference v 2p between t...
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This document was uploaded on 02/27/2014 for the course PHYS 284 at Harvard.
- Fall '10