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arXiv · 2512.09753

Confinement and finite-range effects in a quasi-two-dimensional gas of fermionic dimers

Giovanni Midei·Jordi Boronat·Grigory E. Astrakharchik
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Abstract

We investigate the ground-state properties of ultracold two-component Fermi gases in the presence of a transverse harmonic potential, focusing on the strongly interacting regime in which pairs of fermions form tightly bound molecules. Using the fixed-node diffusion Monte Carlo method, we calculate the equation of state and density profiles for the full fermionic system, which allows us to address the importance of finite-range corrections arising from the internal fermionic structure of the dimers. We interpret the results in terms of a molecular Bose gas in quasi-two-dimensional confinement and compare them with theoretical predictions for a weakly interacting two-dimensional Bose gas, identifying the range of validity of mean-field and beyond-mean-field descriptions. We also develop an analytical theory for the transverse density profile, capturing its broadening with increasing interaction strength. This work provides a benchmark for an effective bosonic description of strongly bound fermionic dimers and offers new insights into confinement-induced dimensional effects.

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Giovanni Midei, Jordi Boronat, Grigory E. Astrakharchik. 2025-12-10. Confinement and finite-range effects in a quasi-two-dimensional gas of fermionic dimers. https://doi.org/10.1103/lr46-r6wg

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