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SUMMARY:Probing matter waves with a dilute-gas Bose-Einstein condensate: n
 ew experiments with an atom laser - Maren Mossman (University of San Diego
 )
DTSTART:20221209T113000Z
DTEND:20221209T120000Z
UID:TALK183809@talks.cam.ac.uk
DESCRIPTION:Dilute-gas Bose-Einstein condensates (BECs) are a prime tool f
 or the investigation of matter wave dynamics. While most experiments to da
 te have been done with trapped BECs where interatomic interactions play a 
 prominent role\, these systems can also be manipulated in the opposite reg
 ime. By coherently outcoupling atoms from a trapped BEC\, a free-falling s
 tream of matter waves can be generated\, called an atom laser. While previ
 ous experiments with atom lasers have mainly focused on the divergence of 
 coherence of these streams\, here we present studies geared towards fluid 
 flow investigations. We describe advanced experimental techniques\, such a
 s fluid flow tracing to follow the flow\, and atom interferometric techniq
 ues to characterize differential potentials. As an application\, we detail
  a set of experiments observing caustics in an accelerated flow\, which re
 lates these systems to the broad field of catastrophe theory. We compare i
 mages obtained with pulsed vs. continuous output coupling\, and observe a 
 geometric transition from attached fan-like features to detached bow shock
 -like features when the atom laser encounters a repulsive barrier. These e
 xperiments provide a first glimpse at a new generation of fluid flow exper
 iments with BECs.\nThis work is supported by NSF under grant number PHY-22
 07588 and by the Henry Luce Foundation in connection to the Clare Boothe L
 uce Professorship Program. Partial support provided by NSF grants DMS-1941
 489 and PHY-2137848.
LOCATION:Seminar Room 1\, Newton Institute
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