Novel physics of polar molecules in optical lattices

偶极-偶极相互作用的长程各向异性特征导致了偶极气体中丰富的新物理，最近关于原子磁偶极子的实验已经部分揭示了这一点。最近关于异核分子的实验使人们能够预见在未来的未来，一种由极性分子组成的量子简并气体。与相对较弱的原子磁偶极子相反，极性分子的电偶极矩可能非常大，如果在外部电场的适当取向下，电偶极-偶极相互作用可能完全主导系统。对于深光学晶格中的极性分子来说，这可能特别引人注目，在那里，偶极-偶极相互作用允许不同位置的分子之间即使没有跳跃也能产生强烈的相互作用。这项建议侧重于这种站点间耦合所带来的新效应。弱偶极子可能导致格点间混合激发，导致不稳定性增强。更令人着迷的是，强偶极子可能会导致位于不同位置的粒子形成复合体。我们特别计划研究二势垒势中玻色和费米气体中的对超流和类BCS配对。该项目将通过研究极性分子的细丝，以及细丝的理想气体和相互作用气体的物理来完成。

The long-range anisotropic character of the dipole-dipole interaction leads to a wealth of new physics in dipolar gases, already partially unveiled by recent experiments on atomic magnetic dipoles. Recent experiments on heteronuclear molecules allow to foreseeing a quantum degenerate gas of polar molecules in the next future. Contrary to the relatively weak atomic magnetic dipoles, the electric dipole moment of polar molecules may be extraordinarily large, and if properly oriented by an external electric field, the electric dipole-dipole interaction may completely dominate the system. This may be particularly striking for polar molecules in deep optical lattices, where the dipole-dipole interaction allows for a strong interaction of molecules at different sites even without hopping. This proposal focuses on the novel effects introduced by this inter-site coupling. Weak dipoles may lead to inter-site hybrid excitations, and the enhancement of instabilities. Even more fascinatingly, strong dipoles may induce the formation of composites of particles lying at different sites. We plan in particular the study of pair-superfluidity and BCS-like pairing in Bose and Fermi gases in two-well potentials. The project will be completed by the study of filaments of polar molecules, and the physics of ideal and interacting gases of filaments.