With a Bose-Einstein condensate of cesium atoms, scientists at the Institute for Experimental Physics of the University of Innsbruck have created one dimensional structures in an optical lattice of laser light. In these quantum lattices or wires the single atoms are aligned next to each other with laser light preventing them from breaking ranks. Delete using an external magnetic field allows the physicists to tune the interaction between the atoms with high precision and this set-up provides an ideal laboratory system for the investigation of basic physical phenomena.
Physicists can observe quantum mechanical phase transitions using ultracold atoms (yellow) in optical lattices (white surface). Originally, the existence of phase transitions was predicted for certain metals and they describe the transition from a conductor to an insulator. For weak interactions the particles are spread out over the lattice in a superfluid state (front); a deep lattice potential is necessary to confine them into single lattices (back). Uni Innsbruck
For strong interactions the particles are already structured (front) and a weak optical lattice is sufficient for immediate pinning of the atoms (back). Uni Innsbruck
“Interaction effects are much more dramatic in low-dimensional systems than in three dimensional space,“ explains Hanns-Christoph Nägerl. Thus, these structures are of high interest for physicists. It is difficult to study quantum wires in condensed matter, whereas ultracold quantum gases provide a versatile tunable laboratory system. And these favorable experimental conditions open up new avenues to investigate novel fundamental phenomena in solid-state or condensed matter physics such as quantum phase transitions.Quantum phase transition
Publication: Pinning quantum phase transition for a Luttinger liquid of strongly interacting bosons. Elmar Haller, Russell Hart, Manfred J. Mark, Johann G. Danzl, Lukas Reichsöllner, Mattias Gustavsson, Marcello Dalmonte, Guido Pupillo, Hanns-Christoph Nägerl. Nature 29 July 2010. doi: 10.1038/nature09259 (http://dx.doi.org/10.1038/nature09259)Contact:
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