Quantum Matter Seminar: Dr. Charles Brown, Yale
Transport of a Quantum Gas through Band Structure Singularities
Location: 1080 Physics Research Building, Smith Seminar Room
Faculty Host: Nandini Trivedi
Abstract: Ultracold-atom quantum simulators are powerful experimental tools that provide insight into the properties of crystalline solids. In the context of the physics of crystals, these simulators allow for study of the local geometry and global topology of the space in which the wave functions live, which is important for explaining exotic material properties, such as quantum Hall effects and orbital magnetism. In this talk I will describe our recent experimental studies of band-structure singularities in a honeycomb optical lattice, performed by investigating a non-Abelian transformation produced by transport of atoms directly through singular points. We produce a Bose-Einstein condensate and load it into one band of an optical honeycomb lattice, before accelerating the atoms along a quasi-momentum trajectory that enters, turns, and then exits the singularities at linear and quadratic touching points of the band structure. From measurements of the band populations after transport we identify topological winding numbers for these singularities to be 1 and 2, respectively.