Superconducting materials transport current with no heat dissipation , a property partly explained, according to the Bardeen-Cooper-Schrieffer theory, by the formation of electron pairs . A better understanding of this mechanism would help explain the inner workings of certain “high critical temperature” superconductors . One approach to explore this kind of phenomena is to perform quantum simulations, by manipulating neutral fermionic atoms that interact attractively (the minimal ingredients of superconductivity theory) in well-controlled experiments. Scientists working as part of an international collaboration led by a CNRS team and ENS-PSL have, for the first time, shown that fermions are not simply pairing within these systems: they also repel other neighbouring particle couples, like dancing couples keeping distance from each other in a ballroom. This dual pairing phenomenon was demonstrated in a study published in Physical Review Letters on April, 15th.
© Tim de Jongh / Laboratoire Kastler Brossel. Adapted from Daix et al., PRL (à paraître en Mars 2026).
To identify this fermionic behaviour, the scientists used a continuum quantum gas microscope, a technique developed at CNRS that can “photograph” matter at the atomic scale. By cooling lithium atoms – which are fermions – down to temperatures approaching absolute zero, the team was able to observe each particle, and to then reconstruct their spatial arrangement, which they compared to advanced numerical calculations.
This research establishes new avenues to better understand complex quantum properties that could eventually guide industrial actors in designing more efficient superconducting devices.
Bibliography
Observing Spatial Charge and Spin Correlations in a Strongly-Interacting Fermi Gas. Cyprien Daix, Maxime Dixmerias, Yuan-Yao He, Joris Verstraten, Tim de Jongh, Bruno Peaudecerf, Shiwei Zhang, Tarik Yefsah, Physical Review Letters, April, 15th 2026.
Source:
https://www.cnrs.fr/en/press/waltz-fermions-under-microscope
