Polaron-molecule transitions in a two-dimensional Fermi gas
Polaron-molecule transitions in a two-dimensional Fermi gas
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DOI：
10.1103/physreva.83.051603
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发表时间：
2011-02
影响因子：
2.9
通讯作者：
M. Parish
中科院分区：
文献类型：
--
作者：
M. Parish
本文研究了二维空间中自旋向下的杂质原子与自旋向上的费米气体的吸引相互作用问题。我们考虑的情况下，杂质的质量大于或等于自旋的费米子的质量。使用变分方法，我们解决了以前研究提出的问题，并表明实际上在2D中极化子和分子（二聚体）基态之间存在跃迁。对于分子态，我们在费米海上采用了一个单粒子-空穴激发的变分波函数，发现在无限杂质质量的极限下，它的能量与精确解的能量相匹配。因此，我们希望变分方法提供一个可靠的工具，调查二维系统。
We address the problem of a single "spin-down" impurity atom interacting attractively with a spin-up Fermi gas in two dimensions (2D). We consider the case where the mass of the impurity is greater than or equal to the mass of a spin-up fermion. Using a variational approach, we resolve the questions raised by previous studies and show that there is, in fact, a transition between polaron and molecule (dimer) ground states in 2D. For the molecule state, we use a variational wave function with a single particle-hole excitation on the Fermi sea and we find that its energy matches that of the exact solution in the limit of infinite impurity mass. Thus, we expect the variational approach to provide a reliable tool for investigating 2D systems.