论文标题
量子关键金属在限制中的不稳定性$ n_f \ rightarrow0 $
Instabilities of quantum critical metals in the limit $N_f\rightarrow0$
论文作者
论文摘要
我们在2+1个维度中研究了一个模型，该模型由$ n_f $ fermions的费米表面组成，该模型与量子临界点附近的标量波动（QCPS）相连。 $ n_f \ rightArrow0 $限制使我们能够非扰动计算费米昂相关函数的远程行为。我们使用它来计算零QCP附近的电荷，旋转和配对，并在零和有限温度下计算零和有限的订单参数间隙。虽然波动抹掉了费米子准颗粒，但我们发现QCP的整体效果会导致配对增强。我们还找到QCP，其中波动诱导自旋和电荷密度波不稳定性，以在$ t = 0 $的有限订单参数波动间隔间隔间隔间隔内。我们还原在$ n_f \ rightarrow0 $限制中被抑制的图的一个子集，所有图表带有内部费米昂循环，最多具有2个顶点，并且发现这不会改变相关器的长距离行为，除了QCPS处于QCPS的权利。
We study a model in 2+1 dimensions composed of a Fermi surface of $N_f$ flavors of fermions coupled to scalar fluctuations near quantum critical points (QCPs). The $N_f\rightarrow0$ limit allows us to non-perturbatively calculate the long-range behavior of fermion correlation functions. We use this to calculate charge, spin and pair susceptibilities near different QCPs at zero and finite temperatures, with zero and finite order parameter gaps. While fluctuations smear out the fermionic quasiparticles, we find QCPs where the overall effect of fluctuations leads to enhanced pairing. We also find QCPs where the fluctuations induce spin and charge density wave instabilities for a finite interval of order parameter fluctuation gaps at $T=0$. We restore a subset of the diagrams suppressed in the $N_f\rightarrow0$ limit, all diagrams with internal fermion loops with at most 2 vertices, and find that this does not change the long-range behavior of correlators except right at the QCPs.
