Quasi-1D Fermi Gases with Spin Imbalance

We report investigations of the spin density in spin-imbalanced Fermi gases confined to 1D tubes using a 2D optical lattice. Measurements of density profiles along the tubes reveal phase transitions between partially polarized superfluid cores and either ferromagnetic or BCS-like wings.\footnote{Y.A. Liao et~al., Nature 467, 567 (2010)} Variations of these phase boundaries with temperature can reveal quantum critical behavior.\footnote{X.W. Guan and T.-L. Ho, PRA 84, 023616 (2011)} Weak tunneling between the tubes should stabilize long-range ordering in the gas, increasing the chance of observing FFLO physics.\footnote{M. M. Parish et~al., PRL 99, 250403 (2007)}