刚性转子分子玻色-爱因斯坦凝聚体的 Bogoliubov 理论
Bogoliubov theory of a Bose-Einstein condensate of rigid rotor molecules
AI总结：
本文研究准二维刚性转子分子 BEC 在外电场和偶极相互作用下的基态与低能激发，揭示完全极化时的密度波不稳定性及弱场下面内极化导致的全局倾斜不稳定性。
摘要：
我们考虑通过谐振囚禁被限制在准二维中的刚性转子分子的 BEC。分子受到使气体极化的外电场作用，并通过偶极-偶极相互作用发生相互作用。我们给出了系统基态和低能激发的描述，包括对平均场能量、极化和稳定性的分析。在大电场下，气体变得完全极化，我们重现了极性 BEC 中出现的著名密度波不稳定性。在较小的外加电场下，气体形成面内极化，随着分子“倾斜”，导致一种新的全局不稳定性出现。这些不稳定性的特征通过动量空间密度-密度结构因子得到阐明。极化面内分量的自旋-自旋结构因子在零动量处的峰值表明，倾斜不稳定性是一种类似声子的全局不稳定性。
英文摘要：
We consider a BEC of rigid rotor molecules confined to quasi-2d through harmonic trapping. The molecules are subjected to an external electric field which polarizes the gas, and the molecules interact via dipole-dipole interactions. We present a description of the ground state and low-energy excitations of the system including an analysis of the mean-field energy, polarization, and stability. Under large electric fields the gas becomes fully polarized and we reproduce a well known density-wave instability which arises in polar BECs. Under smaller applied electric fields the gas develops an in-plane polarization leading to the emergence of a new global instability as the molecules "tilt". The character of these instabilities is clarified by means of momentum-space density-density structure factors. A peak at zero momentum in the spin-spin structure factor for the in-plane component of the polarization indicates that the tilt instability is a global phonon-like instability.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
