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Résumé |
Self-binding in Bose-Bose atomic mixtures with zero-range interactions has received lots of theoretical [1] and experimental [2] attention in the recent years, and a few studies also discussed Bose-Fermi droplets [3]. Fermi-Fermi mixtures with zero-range interspecies attraction, however, are not expected to display self-bound states, since the fermions of one species should overcome a strong Pauli pressure to bind the fermions of the other. This repulsion is, in fact, the fundamental mechanism that provides the stability of atomic Fermi mixtures along the BCS-BEC crossover, in which the dimers repel and do not form larger clusters [4].
In our work [5], we find that a 1D Fermi-Fermi mixture with sufficiently large mass imbalance can form a self-bound state in the thermodynamic limit. This result elaborates our previous few-body analyses [6], and it is based on a mean-field theory in which the heavy fermions are described within the Thomas-Fermi approximation, which is exact in the limit of large mass ratios. Our work sets the basis for understanding liquid-like states in fermionic gases.\\
[1] D. S. Petrov, Phys. Rev. Lett. 115, 155302 (2015).\\
[2] C. R. Cabrera, et al., Science 359, 301 (2018).\\
[3] D. Rakshit, et al., New J. Phys. 21, 073027 (2019); T. Karpiuk, et al., New J. Phys. 22, 103025 (2020).\\
[4] D. S. Petrov, C. Salomon, and G. V. Shlyapnikov, Phys. Rev. Lett. 93, 090404 (2004).\\
[5] J. Givois, A. Tononi, and D. S. Petrov, SciPost Phys. 14, 091 (2023).\\
[6] A. Tononi, J. Givois, and D. S. Petrov, Phys. Rev. A 106, L011302 (2022). |
