论文标题
在金属中的量子关键点处的超导性与非Fermi液体之间的相互作用。 iii:$γ$模型及其相位图,$γ= 1 $
Interplay between superconductivity and non-Fermi liquid at a quantum-critical point in a metal. III: The $γ$ model and its phase diagram across $γ= 1$
论文作者
论文摘要
在本文中,我们继续分析金属中的配对与非fermi液体行为之间的相互作用,用于一组具有有效动力学电子电子相互作用$ V(ω_m)\ Propto 1/|ω_m|^γ$($γ$ -model)的量子临界模型。我们分析了原始模型及其扩展,其中我们引入了一个额外的参数$ n $,以说明粒子孔和粒子粒子通道中的非平等相互作用。在之前的两篇论文(Arxiv:2004.13220和Arxiv:2006.02968)中,我们考虑了$ 0 <γ<1 $ $ 0 <γ<1 $,并认为(i)在$ t = 0 $中,存在无限的离散拓扑上不同的间隙功能,$δ_n(ω_m)$ spate $ spatsial spatsir andnemmenty和Δ终止于特定的$ t_ {p,n} $。在本文中,我们分析了系统行为如何在$γ<1 $和$γ> 1 $之间变化,均以$ t = 0 $和有限的$ t $变化。限制$γ\ to 1 $是由于$ \ intdΩ_mv(ω_m)$的非红外差异而是单数的,并且系统行为对采取此限制的方式非常敏感。我们表明,对于$ n = 1 $,差距方程中的发散取消,$Δ_n(ω_m)$逐渐通过$γ= 1 $在$ t = 0 $和有限的$ t $中逐渐发展。对于$ n \ neq 1 $,发散的条款不会取消,并且以$γ> 1 $的形式出现了质性的新行为。也就是说,$Δ_n(ω_m)$的形式定性地更改,而冷凝能的频谱则在$ t = 0 $的情况下$ e_ {c,n} $变为连续。我们引入了该模型的不同扩展,该模型没有奇异性,价格为$γ> 1 $。
In this paper we continue our analysis of the interplay between the pairing and the non-Fermi liquid behavior in a metal for a set of quantum-critical models with an effective dynamical electron-electron interaction $V(Ω_m) \propto 1/|Ω_m|^γ$ (the $γ$-model). We analyze both the original model and its extension, in which we introduce an extra parameter $N$ to account for non-equal interactions in the particle-hole and particle-particle channel. In two previous papers(arXiv:2004.13220 and arXiv:2006.02968), we considered the case $0 < γ<1$ and argued that (i) at $T=0$, there exists an infinite discrete set of topologically different gap functions, $Δ_n (ω_m)$, all with the same spatial symmetry, and (ii) each $Δ_n$ evolves with temperature and terminates at a particular $T_{p,n}$. In this paper, we analyze how the system behavior changes between $γ<1$ and $γ>1$, both at $T=0$ and a finite $T$. The limit $γ\to 1$ is singular due to infra-red divergence of $\int d ω_m V(Ω_m)$, and the system behavior is highly sensitive to how this limit is taken. We show that for $N =1$, the divergencies in the gap equation cancel out, and $Δ_n (ω_m)$ gradually evolve through $γ=1$ both at $T=0$ and a finite $T$. For $N \neq 1$, divergent terms do not cancel, and a qualitatively new behavior emerges for $γ>1$. Namely, the form of $Δ_n (ω_m)$ changes qualitatively, and the spectrum of condensation energies, $E_{c,n}$ becomes continuous at $T=0$. We introduce different extension of the model, which is free from singularities for $γ>1$.