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Spin-Energy Correlation in Degenerate Weakly-Interacting Fermi Gases

Research paper by S. Pegahan, J. Kangara, I. Arakelyan, J. E. Thomas

Indexed on: 20 Dec '18Published on: 20 Dec '18Published in: arXiv - Condensed Matter - Quantum Gases



Abstract

Weakly interacting Fermi gases in spin-dependent potentials exhibit rich spin transport dynamics, arising from correlations between the motional and spin degrees of freedom. We measure time-dependent spin density profiles for coherently prepared, quantum degenerate clouds of $^6$Li, for time scales up to one second. The profiles are in very good agreement with a one-dimensional mean field description for small s-wave scattering lengths, where the energy changing collision rate is negligible. We present systematic measurements of the zero crossings and magnetic field tuning rates for the s-wave scattering lengths of the three lowest hyperfine states, providing stringent new constraints on the $^6$Li$_2$ molecular potentials. For temperatures in the classical Boltzmann regime, we observe shifts of the zero crossings and modified spin density patterns arising from the energy dependence of the scattering length.