Dissertation Committee Chair: Daniel Lathrop
Committee:
Ian Spielman
Nathan Schine
Thomas Antonsen
Johan Larsson (Dean’s Rep)
Abstract: In this dissertation, I investigate superfluid properties of atomic Bose-Einstein condensates (BECs) including laminar flow experiments that probe the superfluid density and turbulent flow experiments that explore connections to Kolmogorov theory. In this presentations, I focus on a novel technique to measure the BECs velocity field and apply it to turbulence. While turbulence in classical fluids has been extensively studied, there are many open questions in atomic superfluids, particularly regarding the existence of an inertial scale and the applicability of Kolmogorov scaling laws. I developed a velocimetry method, similar to particle image velocimetry using spinor impurities as tracers to measure the velocity field in a spatially resolved way. This enables the first observation of velocity structure functions (VSFs) in BECs, turbulent or otherwise. The observed VSFs reveal that superfluid turbulence in BECs conforms to Kolmogorov theory, including the so-called intermittency evident in both higher-order VSFs and the distribution of velocity increments.