Ultra-dilute droplets of Bose-Bose mixtures that have been recently discovered in systems of cold atoms owe their stability to quantum fluctuations.

In our previous research we have shown that first principle many-body approach, combining quantum Monte Carlo simulations and density functional theory enables reliable prediction of their properties.

In this project we want to take a step forward in developing quantum Monte Carlo methods with the goal of exploring the effects of quantum fluctuations in three particularly interesting systems.

1. Compressed Bose-Bose droplets

A characteristic feature of ultradilute droplets is the existence of a critical atom number, which is the minimum number of particles to have a many-body bound state.

We have recently explored how the critical number and the density profile of droplets change when squeezing the drops in one direction, towards the quasi-2D setting(see PRA 109, 013313 (2024)).

droplets
Fig. 1: Density profiles of Bose-Bose droplets [PRA 109, 013313 (2024)].

In this project we want to determine excitations of compressed Bose-Bose droplets, study vortices and investigate the behaviour of impurities.

2. Cold atoms in periodic and quasi-periodic potentials

We want to explore static and dynamic behaviour of cold atoms in periodic and quasi-periodic potentials, with emphasis on ultradilute droplets. Quantum fluctuations in these systems are only starting to be explored, and we expect new phases to be uncovered. We plan also to study dynamics after quenching lattice potential or interaction to understand the role of interactions in quasi-periodic systems far from equilibrium. Non-equilibrium many-body physics has become the focus of many quantum gas experiments and tVMC is ideally suited to simulate them. For chosen systems we will determine the changes of phase diagram with temperature, which will besides the community of ultracold atoms give valuable insight to the community studying adsorption of quantum fluids on substrates.

3. Quantum fluctuations in Bose-Fermi mixtures

Using diffusion Monte Carlo we will study the Bose-Fermi mixture. Varying the interaction we hope to discover and characterize the regime of ultra dilute liquid. We expect our research will be useful for guiding and interpreting future experiments.


1369 days


This work has been supported by the Croatian Science Foundation under the project number IP-2022-10-6144.

Croatian Science Foundation
University of Split
University of Split Faculty of Science
 

Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of Croatian Science Foundation.

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