论文标题
Bogoliubov的Bose-Einstein凝结物的刚性转子分子的凝结理论
Bogoliubov theory of a Bose-Einstein condensate of rigid rotor molecules
论文作者
论文摘要
我们考虑通过谐波捕获局限于准2D的刚性转子分子的BEC。分子受到偏振气体的外部电场，分子通过偶极 - 偶极相互作用相互作用。我们介绍了系统的基态和低能激发的描述，包括对平均场能，极化和稳定性的分析。在大型电场下，气体变得完全极化，我们再现出众所周知的密度波不稳定性，在极地BEC中产生。在较小的施加电场下，气体会形成平面极化，从而导致新的全球不稳定出现，因为分子“倾斜”。这些不稳定性的特征是通过动量空间密度密度结构因子来阐明的。极化平面成分的自旋旋转结构因子的零动量处的峰值表明倾斜不稳定性是全局语音子样不稳定。
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.
