论文标题
埃里亚斯贝格理论中高斯波动的功能综合方法
The functional-integral approach to Gaussian fluctuations in Eliashberg theory
论文作者
论文摘要
超导性的Eliashberg理论基于动力学电子相互作用，而不是BCS理论中存在的静态相互作用。 Eliashberg理论的标准推导基于运动方法方程，该方程结合了某些近似值，例如Migdal的配对顶点的近似值。在本文中，我们提供了基于功能综合的Eliashberg理论的推导，我们还考虑了其高斯 - 透明扩展。该功能方法实现了一种计算平均场方程的自洽方法，该方法是作为鞍点条件出现的，我们在这里观察到，常规的Eliashberg自我能量和配对函数都作为Hubbard-Stratonovich变换。这一事实的重要结果是，它在高斯波动响应中提供了库珀和密度通道相互作用的系统推导。我们还研究了临界温度附近的强耦合波动磁敏感性。
The Eliashberg theory of superconductivity is based on a dynamical electron-phonon interaction as opposed to a static interaction present in BCS theory. The standard derivation of Eliashberg theory is based on an equation of motion approach, which incorporates certain approximations such as Migdal's approximation for the pairing vertex. In this paper we provide a functional-integral-based derivation of Eliashberg theory and we also consider its Gaussian-fluctuation extension. The functional approach enables a self-consistent method of computing the mean-field equations, which arise as saddle-point conditions, and here we observe that the conventional Eliashberg self energy and pairing function both appear as Hubbard-Stratonovich transformations. An important consequence of this fact is that it provides a systematic derivation of the Cooper and density-channel interactions in the Gaussian fluctuation response. We also investigate the strong-coupling fluctuation diamagnetic susceptibility near the critical temperature.
