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SUMMARY:Synthetic magnetic fields for ultracold neutral atoms - Hannah Pri
 ce (University of Cambridge)
DTSTART:20120309T150000Z
DTEND:20120309T153000Z
UID:TALK35988@talks.cam.ac.uk
CONTACT:Daniel Cole
DESCRIPTION:"Y.-J. Lin et al Nature 462\, 628-632 (2009) ":http://www.natu
 re.com/nature/journal/v462/n7273/full/nature08609.html\n\nNeutral atomic B
 ose condensates and degenerate Fermi gases have been used to realize impor
 tant many-body phenomena in their most simple and essential forms without 
 many of the complexities usually associated with material systems. However
 \, the charge neutrality of these systems presents an apparent limitation 
 — a wide range of intriguing phenomena arise from the Lorentz force for 
 charged particles in a magnetic field\, such as the fractional quantum Hal
 l effect in two-dimensional electron systems. The limitation can be circum
 vented by exploiting the equivalence of the Lorentz force and the Coriolis
  force to create synthetic magnetic fields in rotating neutral systems. Th
 is was demonstrated by the appearance of quantized vortices in pioneering 
 experiments on rotating quantum gases\, a hallmark of superfluids or super
 conductors in a magnetic field. However\, because of technical issues limi
 ting the maximum rotation velocity\, the metastable nature of the rotating
  state and the difficulty of applying stable rotating optical lattices\, r
 otational approaches are not able to reach the large fields required for q
 uantum Hall physics. Here we experimentally realize an optically synthesiz
 ed magnetic field for ultracold neutral atoms\, which is evident from the 
 appearance of vortices in our Bose–Einstein condensate. Our approach use
 s a spatially dependent optical coupling between internal states of the at
 oms\, yielding a Berry’s phase sufficient to create large synthetic magn
 etic fields\, and is not subject to the limitations of rotating systems. W
 ith a suitable lattice configuration\, it should be possible to reach the 
 quantum Hall regime\, potentially enabling studies of topological quantum 
 computation.
LOCATION:TCM Seminar Room\, Cavendish Laboratory
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