Gemelke is a physicist whose research focuses on the behavior of atomic gases as they transition from one quantum phase to another at temperatures near absolute zero -- the point at which all random motion ceases. He and his collaborators recently created the first direct images showing the transition between two phases of such "ultracold" gases held in an egg-crate-like container formed by interfering laser beams. These high-resolution images reveal a peculiar self-organization of atoms resembling tiered cakes, which have been dubbed "wedding cake" structures. In other work, Gemelke and his collaborators demonstrated the peculiar effects of quantum mechanics in a rapidly rotating gas of atoms, where whirlpools known as "vortices" begin to overlap. Gemelke's research is an important step toward understanding the complicated and enigmatic quantum mechanics of large numbers of interacting particles at very low temperatures. His research also makes important advances in the categorization of unique forms of matter.