Extended Data Fig. 8: Alternative visualization of the density–density correlation function \({\boldsymbol{\mathscr{C}}}^{{\boldsymbol{(}}{\bf{2}}{\boldsymbol{)}}}\).
From: Observation of Cooper pairs in a mesoscopic two-dimensional Fermi gas
The pair-correlation functions in relative (\({{\mathscr{C}}}_{{\rm{R}}}^{(2)}\)) and centre-of-mass (\({{\mathscr{C}}}_{{\rm{C}}}^{(2)}\))coordinates as a function of the interaction strength EB are shown in a–e and f–j, respectively. The figure represents an alternative method of binning and visualizing the 4D correlation function \({{\mathscr{C}}}^{(2)}\), but is otherwise equivalent to the data shown in Fig. 2. The dashed circle indicates twice the Fermi momentum, 2pF. In relative coordinates (a–e), we find a surplus of particles with momenta of |pR| ≈ 2pF, as expected for the formation of Cooper pairs with atoms located at the opposite ends of the Fermi surface. In the centre-of-mass frame (f–j), emergence of pairing is indicated by a sharp peak at zero momentum that increases in weight with the interaction strength. k–o, Radial integrals of the relative momentum correlation densities in a–e. The error bars represent the standard error of the mean.
