Figure 1

Absorption images and integrated density profiles showing the BEC phase transition for different times $t_{\mathrm{ev}}$ of the evaporative cooling ramp. The images are taken in the horizontal direction at ${45}^{°}$ to the horizontal trap axes, 25 ms after release from the trap. The field of view is $400\times 400\hspace{0.5em}\mu$$\mathrm{m}{}^2$. The solid line represents a fit with a bimodal distribution, while the dashed line shows the Gaussian-shaped thermal part, from which the given temperatures are derived.Reuse & Permissions

Figure 2

The condensate fraction $N_0/N$ as a function of the temperature scaled by the critical temperature of an ideal gas in the thermodynamic limit $T_c^0$. The line shows the behavior expected for an ideal gas. The arrow indicates the expected transition temperature $T_c=0.85T_c^0$ when interactions and minor contributions from finite-size effects are taken into account.Reuse & Permissions

Figure 3

Inversion of the aspect ratio during the expansion of a pure BEC. The images (fields of view $300\times 300\hspace{0.5em}\mu {\mathrm{m}}^2$) are taken along the horizontal direction and show the BEC in the trap (left) and after 25 ms free expansion (right).Reuse & Permissions