Dimensional crossover in ultradilute Bose-Bose liquid mixtures
Year: 2026
Type: article
Abstract: We study ultradilute $^{39}$K Bose-Bose bulk mixtures and droplets in an external harmonic potential that confines them in one spatial direction towards the two-dimensional (2D) limit. Equations of state for several confinements are obtained with quantum Monte Carlo (QMC) at $T=0$, using interaction potentials that include information on the $s$-wave scattering length $a$ and the effective range $r_{\rm eff}$. Performing the calculations using two different interaction potential models we have determined the range of confinements for which equations of state are universal in terms of $a$ and $r_{\rm eff}$. Based on the QMC equation of state, we develop a 2D QMC density functional for each confinement strength and use it together with the local density approximation to determine properties of the self-bound drops. For moderate squeezing, energies and droplet profiles obtained using the 2D QMC functional agree well with those obtained using 3D functionals, while offering a substantial reduction in computational cost, and a consistent approach in crossover to 2D. Noticeably, our results approach 2D mean-field (MF) + Lee-Huang-Yang (LHY) predictions only for the most strongly confined systems for which universality in terms of $a$ and $r_{\rm eff}$ is observed. This implies a very narrow range of confinements for which 2D LHY functionals are applicable, which affects the study of vortices using 2D functionals.
Source: Physical Review Research
DOI: 10.1103/zpp2-x8y5
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,625
Awards: G1175115578, G121809054, G1855990336, G210041235, G2262748287, G2309174360, G2601397997, G2660406951, G279363373, G300979063, G34346518, G3480869486, G3518538256, G3611179903, G3681454997, G4042783231, G417969858, G425668148, G430777504, G4442677895, G4526231891, G464105488, G4938354709, G5080475149, G5195188938, G5421974903, HRZZ DOK-NPOO — University of Split, Faculty of Science, G702465783, G7084143925, Exploring quantum fluctuations in cold atom systems, G897484643, G99296377
OpenAlex ID: W7171627908