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“Self-bound fermionic mixtures in 1D” Andrea Tononi

Jan 25, 2023 from 12:30 PM to 01:30 PM
UPC campus nord, B4-212 (aula seminari)
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Wednesday, 25th of January 2023 at 12:30

UPC campus nord, B4-212 (aula seminari)


Andrea Tononi

LPTMS, Université Paris Sud, Francia

 “Self-bound fermionic mixtures in 1D”


Self-binding in Bose-Bose mixtures has received lots of theoretical [1] and experimental [2] attention in recent years, and a few studies discussed also Bose-Fermi droplets [3]. Fermi-Fermi mixtures with 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 stability of Fermi mixtures along the BCS-BEC crossover, whose dimers repel and do not form larger clusters [4].

In our recent work [5], surprisingly, we find that one-dimensional Fermi-Fermi mixtures 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 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 future studies of self-bound fermions in higher-dimensional cases, which can shed light on the fundamental behavior of macroscopic fermionic aggregates.


[1] D. S. Petrov, Quantum Mechanical Stabilization of a Collapsing Bose-Bose Mixture, Phys. Rev. Lett. 115, 155302 (2015).
[2] C. R. Cabrera, et al., Quantum liquid droplets in a mixture of Bose-Einstein condensates, Science 359, 301 (2018).
[3] D. Rakshit, et al., Self-bound Bose–Fermi liquids in lower dimensions, New J. Phys. 21, 073027 (2019); T. Karpiuk, et al., Bistability of Bose–Fermi mixtures, New J. Phys. 22, 103025 (2020).
[4] D. S. Petrov, C. Salomon, and G. V. Shlyapnikov, Weakly bound dimers of fermionic atoms, Phys. Rev. Lett. 93, 090404 (2004).
[5] J. Givois, A. Tononi, and D. S. Petrov, Self-binding of one-dimensional fermionic mixtures with zero-range interspecies attraction, arXiv:2207.04742.
[6] A. Tononi, J. Givois, and D. S. Petrov, Binding of heavy fermions by a single light atom in one dimension, Phys. Rev. A 106, L011302 (2022).