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arXiv 1502.00900cond-mat.quant-gas
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强极化费米混合体中的准粒子散射率

Quasiparticle scattering rate in a strongly polarised Fermi mixture

Rasmus Søgaard Christensen, Georg M. Bruun

摘要:

我们分析了杂质原子在费米海中的散射率随动量和温度的变化关系。截面计算使用微观多通道理论的费什巴赫共振散射,包括有限范围和介质的影响。我们发现,对相关显着增加的横截面强相互作用接近幺正制度。这些对相关引起的截面的分子极点在负能量上的BEC侧的共振,这顺利地演变成共振在正散射能量与非零虚部的BCS侧。这种共振类似于相应的粒子数平衡系统的超流配对。利用费米液体理论,我们然后表明,杂质原子的低温散射率显着增加,由于这些对相关低动量。我们表明,有限范围和质量不平衡的影响是显着的实验相关的$^6$锂- $^{40}$ K混合物,我们最后讨论了如何使用射频光谱和玻色-费米混合物的散射率可以测量。

英文摘要:

We analyse the scattering rate of an impurity atom in a Fermi sea as a function of momentum and temperature in the BCS-BEC crossover. The cross section is calculated using a microscopic multichannel theory for the Feshbach resonance scattering, including finite range and medium effects. We show that pair correlations significantly increase the cross section for strong interactions close to the unitarity regime. These pair correlations give rise to a molecule pole of the cross section at negative energy on the BEC side of the resonance, which smoothly evolves into a resonance at positive scattering energy with a non-zero imaginary part on the BCS side. The resonance is the analogue of superfluid pairing for the corresponding population balanced system. Using Fermi liquid theory, we then show that the low temperature scattering rate of the impurity atom is significantly increased due to these pair correlations for low momenta. We demonstrate that finite range and mass imbalance effects are significant for the experimentally relevant $^6$Li-$^{40}$K mixture, and we finally discuss how the scattering rate can be measured using radio-frequency spectroscopy and Bose-Fermi mixtures.

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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