Fermionic quantum systems with a tuneable atom number have proven to be a viable platform for exploring the emergence of many-body phenomena. In our experimental setup we can deterministically prepare few-body fermionic quantum systems in a two-dimensional harmonic potential with stable closed-shell configurations.
Using a time-of-flight expansion in combination with our imaging technique, which provides spin and single atom resolution simultaneously, we can explore correlations of atoms in different spin states in momentum space. This has recently lead us to the observation of Cooper pairs (1). We have recently extended our imaging technique to real space, by magnifying the matterwave. Similar to technique demonstrated in (2), we have developed a matterwave optics technique to expand the wavefunction prior to fluorescence imaging. This allows us to resolve it with our existing imaging setup, giving us access to correlations and small structures in both real and momentum space.
We now utilize this expanded imaging scheme to investigate the emergence of hydrodynamic behaviour in dependence on particle number and interaction strength. By preparing closed shell configurations of an elliptic harmonic oscillator, we can directly observe the inversion of the aspect ratio at particle numbers as low as five atoms per spin state. Additionally, we see an enhancement of pair correlations after an interacting expansion. We directly study this formation of pairs by magnifying the real space wave function after different short interacting expansion times.
(1) Holten et al. arXiv: 2109.11511 (2021) accepted in Nature
(2) Asteria et al. Nature 599, 571-575 (2021)
|Presenter name||Sandra Brandstetter|
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