JQI Special Seminar - Lin Su

Speaker:  Lin Su (Columbia, formerly Harvard)
Title:  From Microscopic Control to Emergent Phases: Long-Range Quantum Matter with Dipolar Gases
Abstract:  Emergent quantum phases often arise when interactions extend beyond nearest neighbors, giving rise to frustration, topology, and competing orders. Dipolar quantum gases offer a uniquely tunable and microscopically controlled platform for engineering and probing such long-range quantum matter. In this talk, I present two complementary experimental platforms that advance this frontier. 

First, we realize a dipolar quantum gas microscope using magnetic atoms in a small-spacing optical lattice, where coherent tunneling competes directly with tunable dipole–dipole interactions. An accordion-lattice expansion enables rapid, high-fidelity site-resolved imaging. With this platform, we observe dipolar quantum solids exhibiting checkerboard and stripe order and identify interaction-driven topological transitions through measurements of nonlocal string order. 

I then turn to ultracold ground-state NaCs molecules, where long-lived molecular Bose–Einstein condensates reach strongly interacting dipolar regimes previously limited by inelastic loss. Microwave dressing tunes interaction strength and anisotropy, producing droplet arrays and related interaction-driven structures. These advances set the stage for unconventional Hubbard and spin models with tunable long-range couplings in optical lattices.