Stability and excitations of a bilayer of strongly correlated dipolar Bosons

Abstract

We study correlation effects and excitations in a dipolar Bose gas bilayer which is modeled by a one-dimensional double well trap that determines the width of an individual layer, the distance between the two layers, and the height of the barrier between them. For the ground state calculations we use the hypernetted--chain Euler Lagrange method and for the calculation of the excitations we use the correlated basis function method. We observe instabilities both for wide, well-separated layers dominated by \emph{intra-layer} attraction of the dipoles, and for narrow layers that are close to each other dominated by \emph{inter-layer} attraction. The behavior of the pair distribution function leads to the interpretation that the monomer phase becomes unstable when pairing of two dipoles becomes energetically favorable between or within layers, respectively. In both cases we observe a tendency towards "rotonization", i.e. the appearance of a soft mode with finite momentum in the excitation spectrum. The dynamic structure function is not simply characterized by a single excitation mode, but has a non-trivial multi-peak structure that is not captured by the Bijl-Feynman approximation. The dipole-dipole interaction between different layers leads to additional damping compared to the damping obtained for uncoupled layers.

11 pages

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Cited by in corpus (10)

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• Analysis of dynamical effects in the uniform electron liquids with the self-consistent method of moments complemented by the Shannon information entropy and the path-integral Monte-Carlo simulations
• Dipolar Bilayer with Antiparallel Polarization -- a Self-Bound Liquid
• Gapped spectrum in pair-superfluid bosons
• Correlations in the low-density Fermi gas: Fermi-Liquid state, Dimerization, and BCS Pairing
• Striped Ultradilute Liquid of Dipolar Bosons in Two Dimensions
• The Multi-component Correlated Basis Function Method and its Application to Multilayered Dipolar Bose Gases
• Dynamic properties and the roton mode attenuation in the liquid 3He: an ab initio study within the self-consistent method of moments
• Density engineering via inter-condensate dipole-dipole interactions
• Quantum phases of hard-core dipolar bosons in coupled 1D optical lattices