论文标题
BCS费米超级流体中重北极子的精确准粒子特性
Exact quasiparticle properties of a heavy polaron in BCS Fermi superfluids
论文作者
论文摘要
我们使用精确的功能决定词方法介绍了沉浸在相互作用的费米超流体中的重杂质的Ramsey反应和射频光谱。我们通过常规的Bardeen-Cooper-Schrieffer理论描述了费米超流体，并研究了两种光谱镜揭示的配对差距在准片粒性能上的作用。一对破裂的能量成本阻止了Anderson \ texquoteright S正交性灾难发生，该灾难发生在非相互作用的费米气体中，并允许在可溶解的重型杂质限制中存在极化子准颗粒。因此，我们严格地证实了诸如深色连续体，分子连续体和排斥偏光元等显着特征。对于在有限温度下的磁杂质散射，我们预测与亚间隙Yu-Shiba-Rusinov结合状态相关的其他共振，其位置可用于测量超流体配对间隙。对于在零温度下的非磁性散射，我们出人意料地发现了未阻尼的排斥极性。这些精确的结果很容易在具有较大质量比的Bose-Fermi混合物的量子气体实验中观察到。
We present the Ramsey response and radio-frequency spectroscopy of a heavy impurity immersed in an interacting Fermi superfluid, using exact functional determinant approach. We describe the Fermi superfluid through the conventional Bardeen-Cooper-Schrieffer theory and investigate the role of the pairing gap on quasiparticle properties revealed by the two spectroscopies. The energy cost for pair breaking prevents Anderson\textquoteright s orthogonality catastrophe that occurs in a non-interacting Fermi gas and allows the existence of polaron quasiparticles in the exactly solvable heavy impurity limit. Hence, we rigorously confirm the remarkable features such as dark continuum, molecule-hole continuum and repulsive polaron. For a magnetic impurity scattering at finite temperature, we predict additional resonances related to the sub-gap Yu-Shiba-Rusinov bound state, whose positions can be used to measure the superfluid pairing gap. For a non-magnetic scattering at zero temperature, we surprisingly find undamped repulsive polarons. These exact results might be readily observed in quantum gas experiments with Bose-Fermi mixtures that have a large-mass ratio.
