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Cornell University
LASSP -  Laboratory of Atomic and Solid State Physics

Cornell Laboratory for Atomic and Solid State Physics

Matthew Reichl and Erich Mueller describe new way for lasers to generate flow in atomic clouds

Recent theoretical work by Reichl and Mueller (to be published in Physical Review A) describes how to engineer and probe an exotic state of matter called a "topological insulator" in a gas of atoms cooled to temperatures near absolute zero. Topological insulators have the remarkable property that they act like insulators in their interior but  can conduct along their surfaces or edges. They are not only of fundamental interest to physicists but have important applications in electronics and quantum computation. To engineer such a state, the authors imagine an experiment where ultracold atoms are trapped in a lattice with laser beams and made to behave like a topological insulator by modulating the lasers to change the shape of the lattice periodically in time. The smoking-gun signature of a topological insulator is the presence of "edge states"- conduction channels appearing at the boundaries of the system. Using computer simulations, the authors demonstrate how a clump of atoms released at the boundary will remain grouped together and will propagate- or "conduct"- along the boundary (see attached animation). Reichl and Mueller's proposal provides a straightforward and accessible way to generate and probe topological insulators in experiments using ultracold atoms. Such experiments will allow physicists to learn more about this fascinating state of matter.

atoms conduct along boundary of topological insulator system