Observation of a Two-Dimensional Fermi Gas of Atoms

We have prepared a degenerate gas of fermionic atoms which move in two dimensions while the motion in the third dimension is “frozen” by tight confinement and low temperature. In situ imaging provides direct measurement of the density profile and temperature. The gas is confined in a defect-free optical potential, and the interactions are widely tunable by means of a Fano-Feshbach resonance. This system can be a starting point for exploration of 2D Fermi physics and critical phenomena in a pure, controllable environment.

Figure 1

Trapping ultracold atoms in antinodes of a standing optical wave. The isolated clouds of atoms shown in dark red, the standing-wave intensity shown in light purple.

Figure 2

In situ image of the column density distribution $n_2(x,z)$ of the Fermi gas trapped in antinodes of a standing optical wave. Each cloud is a 2D system. The number of atoms per spin state per square micron is coded in the tones of gray. The meaning of the tones is shown on the right.

Figure 3

One-dimensional density profile in a single cloud obtained by integrating 3D density distribution along $y$ and $z$. The dots are the data averaged over the 21 central clouds. The black solid curve is the fit of formula (3) to the data. The blue dashed curve is the fit of a Gaussian distribution.