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arXiv 1111.7114cond-mat.quant-gasquant-ph
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新型二维极性分子费米液体

Novel Fermi Liquid of 2D Polar Molecules

Zhen-Kai Lu, G. V. Shlyapnikov

摘要:

研究了偶极矩$d$垂直于平动平面的单组分费米极性分子弱相互作用二维气体的费米液体性质。这种几何形状允许最小化由于反应分子的化学反应的非弹性损失,并在同一时间,提供了一个清晰的描述多体(超出平均场)的影响的可能性。分子间偶极-偶极排斥相互作用的长程特性(在大距离$r$上的尺度为$1/r^3$)使得该问题与已知的具有排斥接触种间相互作用的两种费米气体的问题截然不同。我们解决了低能散射问题,并发展了一个超越平均场的多体微扰理论。该理论依赖于小参数$k_Fr_*$的存在,其中$k_F$是费米动量,$r_*=md^2/\hbar^2$是偶极-偶极长度,$m$是分子质量。我们得到的热力学量作为一系列的扩展到二阶$k_Fr_*$,并认为,多体修正的基态能量可以确定在实验中与超冷分子,就像它最近已经做了超冷费米子原子。此外,我们表明,只有多体效应提供零声的存在和计算的声速。

英文摘要:

We study Fermi liquid properties of a weakly interacting 2D gas of single-component fermionic polar molecules with dipole moments $d$ oriented perpendicularly to the plane of their translational motion. This geometry allows the minimization of inelastic losses due to chemical reactions for reactive molecules and, at the same time, provides a possibility of a clear description of many-body (beyond mean field) effects. The long-range character of the dipole-dipole repulsive interaction between the molecules, which scales as $1/r^3$ at large distances $r$, makes the problem drastically different from the well-known problem of the two-species Fermi gas with repulsive contact interspecies interaction. We solve the low-energy scattering problem and develop a many-body perturbation theory beyond the mean field. The theory relies on the presence of a small parameter $k_Fr_*$, where $k_F$ is the Fermi momentum, and $r_*=md^2/\hbar^2$ is the dipole-dipole length, with $m$ being the molecule mass. We obtain thermodynamic quantities as a series of expansion up to the second order in $k_Fr_*$ and argue that many-body corrections to the ground-state energy can be identified in experiments with ultracold molecules, like it has been recently done for ultracold fermionic atoms. Moreover, we show that only many-body effects provide the existence of zero sound and calculate the sound velocity.

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。

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