E1 - Quantum Gases on a Chip
The “chip” experiment is a compact degenerate Fermi-gas machine. Each experimental cycle begins by laser cooling both Rubidium 87 and Potassium 40, and then trapping both species magnetically.
A micofabricated electromagnet compresses the mixture, and allows evaporatively cooled 87Rb, a boson, to act as a cooland for 40K, a fermion. Finally, quantum degeneracy is achieved in a purely optical trap. From this starting point, we have pursued several lines of investigation: (1) the physics of gases whose interactions are unitary, meaning that collisions are as strong as allowed by quantum mechanics; (2) universal relations that emerge from the strength of short-range correlations; (3) pairs of 40K atoms with p-wave orbital wave functions; and (4) non-equilibrium phenomena, such as a transition between dynamical phases.
Team : C. Dale, K. Jackson, H. Lin, S. Smale, K. Xie
E2 - Quantum Gas Microscopy
The “lattice” experiment is built around high-resolution optical microscopy 40K. Ultracold atoms move around the lattice via quantum-mechanical tunnelling, just as electrons hop from site to site in materials. Building on this analogy, we can study many-body paradigms developed for quantum materials, but with neutral fermions instead of with electrons. The advantage of this “quantum simulation” approach is that the system is extremely tuneable, free from impurities, and relatively easy to control. Using these tools, we have explored the origin of resisitivity for interacting fermions in a perfect crystal.
Team : R. Anderson, D. Bates, C Fujiwara, F. Corapi, V. Venu, P. Xu