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Center for Nonlinear Studies |
Physicists have used light and its polarization to elucidate the internal state of atoms since the 19th century. Early in the 20th century, the momentum of light was used to manipulate the center-of-mass motion of atoms. The latter part of the 20th century brought optical pumping, coherent laser excitation, and laser cooling and trapping as tools to affect both the internal and external states of atoms. Bose-Einstein condensation created atomic samples having laser-like deBroglie-wave coherence, and atom optics techniques like Bragg diffraction provided coherent mirrors and beamsplitters for the coherent atoms. An extension of Bragg diffraction, using light beams with orbital angular momentum (angular momentum associated not with the optical polarization, but with the shape of the spatial mode), provided a new tool for coherent manipulation of atomic motion, creating coherent rotation of atom clouds, and persistent flow of superfluid atoms in toroidal traps. In the latest experiments, we have introduced an optical weak-link into the superfluid flow, allowing us to explore the behavior of an atomtronics circuit with an interesting circuit element.
Host: Bob Ecke