Extended Data Fig. 5: Fitting a CW BEC.
We show absorption pictures and their respective fits for two hold times, before (left, thold = 2.2 s) and after (right, thold = 3.2 s) the formation of the BEC. In the top row, we show absorption pictures a, f taken after an 18-ms time-of-flight expansion. In the middle row, we show results of fits b, g to these pictures and the fit residuals c, h. The fits use a 2D density distribution fit function accounting only for a thermal cloud. By contrast, the bottom row shows both fits d, i and residuals e, j with a 2D density distribution fit function including a Thomas–Fermi distribution describing a BEC, in addition to the thermal distribution. In the presence of a BEC, the residual of the thermal-only fit h clearly shows a discrepancy at the BEC location, whereas the residual j demonstrates that the fit accounts for the BEC.
