We have characterized the one-dimensional (1D) to three-dimensional (3D)
crossover of a two-component spin-imbalanced Fermi gas of 6-lithium atoms in a
2D optical lattice by varying the lattice tunneling and the interactions. The
gas phase separates, and we detect the phase boundaries using in situ imaging
of the inhomogeneous density profiles. The locations of the phases are inverted
in 1D as compared to 3D, thus providing a clear signature of the crossover. By
scaling the tunneling rate with respect to the pair binding energy, we observe
a collapse of the data to a universal crossover point at a scaled tunneling
value of 0.025(7).Comment: 5 pages, 4 figure
