Freiburg 2024 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 1: Ultra-cold Atoms, Ions and BEC I (joint session A/Q)
Q 1.7: Talk
Monday, March 11, 2024, 12:45–13:00, HS 1010
Quantum phases of hardcore bosons with repulsive dipolar density-density interactions on two-dimensional lattices — •Jan Alexander Koziol1, Giovanna Morigi2, and Kai Phillip Schmidt1 — 1Department of Physics, Staudtstraße 7, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Germany — 2Theoretical Physics, Saarland University, Campus E2.6, D-66123 Saarbrücken, Germany
We analyse the ground-state quantum phase diagram of hardcore Bosons interacting with repulsive dipolar potentials. The bosons dynamics is described by the extended-Bose-Hubbard Hamiltonian on a two-dimensional lattice The ground state results from the interplay between the lattice geometry and the long-range interactions, which we account for by means of a classical spin mean-field approach. This extended classical spin mean-field theory accounts for the long-range density-density interaction without truncation. The mean-field analysis is limited by the size of the considered unit cells. We consider three different lattice geometries: square, honeycomb, and triangular. In the limit of zero hopping the ground state is always a devil’s staircase of solid (gapped) phases. Such crystalline phases with broken translational symmetry are robust with respect to finite hopping amplitudes. At intermediate hopping amplitudes, these gapped phases melt, giving rise to various lattice supersolid phases, which can have exotic features with multiple sublattice densities. Our results are of immediate relevance for experimental realisations of self-organised crystalline ordering patterns, e.g., with ultracold dipolar atoms in an optical lattice.
Keywords: Bose-Hubbard model; dipolar interactions; optical lattice; devil's staircase; supersolids