Quantum phase diagrams for bosons in hexagonal optical potentials: A continuous-space quantum Monte Carlo study

Abstract:Hexagonal optical lattices, emulating graphene and hexagonal boron nitride (h-BN) structures, provide a versatile platform for exploring strongly correlated quantum matter. Using continuous-space exact diagonalization and quantum Monte Carlo simulations, we investigate the phase diagrams of ultracold bosons in honeycomb and h-BN lattices. For the honeycomb lattice, we find significant deviations from the standard Bose--Hubbard model even for strong lattice amplitudes. We observe suppressed Mott insulator lobes and the absence of higher-order insulating phases, which we attribute to strong density-assisted tunneling effects. In the h-BN case, a rich phase diagram emerges, featuring multiple Mott lobes with various sublattice occupations, driven by the interplay of lattice asymmetry, interactions, and particle filling. Our results highlight the necessity of continuous-space treatments for capturing the full complexity of bosonic quantum phases in hexagonal geometries, paving the way for experimental realizations with ultracold atoms and further theoretical work.

Quantum Gases (cond-mat.quant-gas); Quantum Physics (quant-ph)

arXiv:2605.06171 [cond-mat.quant-gas]

(or arXiv:2605.06171v2 [cond-mat.quant-gas] for this version)

https://doi.org/10.48550/arXiv.2605.06171 Focus to learn more arXiv-issued DOI via DataCite

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