Miscibility-immiscibility transition of strongly interacting bosonic mixtures in optical lattices

Year: 2025

Authors: Bai R., Bandyopadhyay S.

Autors Affiliation: Univ Stuttgart, Inst Theoret Phys 3, D-70550 Stuttgart, Germany; Univ Stuttgart, Ctr Integrated Quantum Sci & Technol, D-70550 Stuttgart, Germany; Leibniz Univ Hannover, Inst Fair Theoret Phys, Appelstr 2, D-30167 Hannover, Germany; Univ Trento, Pitaevskii BEC Ctr, CNR INO, Via Sommar 14, I-38123 Trento, Italy; Univ Trento, Dipartimento Fis, Via Sommar 14, I-38123 Trento, Italy; Trento Inst Fundamental Phys & Applicat, INFN TIFPA, Via Sommar 14, I-38123 Trento, Italy.

Abstract: Interaction plays a key role in the mixing properties of a multicomponent system. The miscibilityimmiscibility transition (MIT) in a weakly interacting mixture of Bose gases is predominantly determined by the strengths of the intra- and intercomponent two-body contact interactions. However, in the strongly interacting regime interaction-induced processes become relevant. Despite previous studies on bosonic mixtures in optical lattices, the effects of the interaction-induced processes on the MIT remains unexplored. In this work, we investigate the MIT in the strongly interacting phases of two-component bosonic mixture trapped in a homogeneous two-dimensional square optical lattice. Particularly we examine the MIT condition when both the components are in superfluid, one-body staggered superfluid, or supersolid phases. Our study uncovers that MIT condition is significantly shaped by the interplay of competing nonlocal intra- and intercomponent densityinduced tunneling effects, as well as off-site interactions. Notably, we demonstrate that the MIT condition for the staggered superfluid phase exhibits an inequality that is inverted compared to the conventional MIT condition associated with superfluid or supersolid phases driven by local contact interactions. In addition, we present the phase diagram of the Bose-Hubbard model incorporating nonlocal processes, derived using a site-decoupling mean-field approach with the Gutzwiller ansatz. Our study contributes to the better understanding of miscibility properties of multicomponent systems in the strongly interacting regime.

Journal/Review: PHYSICAL REVIEW A

Volume: 112 (2)      Pages from: 23313-1  to: 23313-17

More Information: We gratefully acknowledge useful discussions with Philipp Hauke. R.B. acknowledges International Institute of Infor-mation Technology Hyderabad for kind hospitality during the progress of this work. S.B. acknowledges funding by the Next Generation EU, Mission 4 Component 2 CUP E53D23002240006, European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No. 804305), Provincia Autonoma di Trento, Q@TN, the joint laboratory between University of Trento, FBK-Fondazione Bruno Kessler, INFN-National Institute for Nuclear Physics and CNR-National Research Council. R.B. acknowledges the support of the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy – EXC-2123 Quantum-Frontiers-390837967. S.B. acknowledges CINECA for the use of HPC resources under Italian SuperComputing Resource Allocation ISCRA Class-C Projects No. ISSYK-2 (HP10CP8XXF) and No. DISYK (HP10CGNZG9) . Views and opinions expressed are however those of the author (s) only and do not necessarily reflect those of the European Union or European Commission. Neither the European Union nor the granting authority can be held responsible for them.
KeyWords: Quantum Phase-transition; Bose-hubbard Model; Ultracold Atoms; Mott Insulator; Cold Atoms; Superfluid; Dynamics; Gas; Oscillations; Simulations
DOI: 10.1103/r52b-bsrd