论文标题
二维费米系统中的绑定状态具有二次带触摸
Bound states in two-dimensional Fermi systems with quadratic band touching
论文作者
论文摘要
移动杂质颗粒和费米原子之间的结合状态在具有吸引人的种间相互作用的自旋偏置的费米气中已证明。我们研究了浸入具有对称性保护的二次带触摸的二维系统中的移动杂质的结合状态。除了标准的S波相互作用外，我们还考虑了一种各向异性偶极交换相互作用，该相互作用在局部打破了点组对称性。使用弱耦合重新归一化组方法和质量 - 特里米式传播器的梯子近似，我们确定可以通过改变交换相互作用的各向异性来控制结合状态的数量。我们的结果表明，结合能的退化和动量依赖性反映了二次带触摸的某些独特特性。
The formation of bound states between mobile impurity particles and fermionic atoms has been demonstrated in spin-polarized Fermi gases with attractive interspecies interaction. We investigate bound states of mobile impurities immersed in a two-dimensional system with a symmetry-protected quadratic band touching. In addition to the standard s-wave interaction, we consider an anisotropic dipolar exchange interaction that locally breaks point group symmetries. Using a weak-coupling renormalization group approach and a ladder approximation for the impurity-fermion propagator, we establish that the number of bound states can be controlled by varying the anisotropy of the exchange interaction. Our results show that the degeneracy and momentum dependence of the binding energies reflect some distinctive properties of the quadratic band touching.
