发表机构
National Chung Cheng University; National Center for Theoretical Sciences; Rutgers University; Brookhaven National Laboratory; Rochester Institute of Technology; Flatiron Institute（中正大学; 国家理论科学中心; 罗格斯大学; 布鲁克海文国家实验室; 罗切斯特理工学院; 弗莱提伦研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出gRISB理论下的有限温度高斯涨落形式，用于计算响应函数，在二维哈伯德模型中优于标准RISB和RPA，并恢复Kotliar-Ruckenstein响应，直接实频率计算避免数值延拓。
AI 中文摘要
我们提出了一个在幽灵旋转不变奴隶玻色子（gRISB）理论框架内用于响应函数的有限温度高斯涨落形式，并将其应用于二维哈伯德模型。gRISB磁性相边界以及静态自旋和电荷磁化率捕捉了动力学平均场理论（DMFT）的趋势，显著优于标准RISB和随机相位近似（RPA）。在RISB水平上，我们的形式恢复了Kotliar-Ruckenstein响应。动力学磁化率解析出了顺磁子、低能声模和高能哈伯德激发。由于直接在实频率轴上评估，结果避免了马苏巴拉截断、随机采样和数值解析延拓。我们还引入了一个守恒准粒子近似，用戴修饰的格林函数和顶点修正来表达响应。
英文摘要
We propose a finite-temperature Gaussian-fluctuation formalism for response functions within ghost rotationally invariant slave-boson (gRISB) theory and apply it to the two-dimensional Hubbard model. The gRISB magnetic phase boundary and static spin and charge susceptibilities capture the trends of dynamical mean-field theory (DMFT), significantly improving upon standard RISB and the random phase approximation (RPA). At the RISB level, our formalism recovers the Kotliar-Ruckenstein response. The dynamical susceptibilities resolve paramagnons, low-energy sound modes, and high-energy Hubbard excitations. Because they are evaluated directly on the real-frequency axis, the results avoid Matsubara truncation, stochastic sampling, and numerical analytic continuation. We also introduce a conserving quasiparticle approximation that expresses the response in terms of dressed Green's functions and vertex corrections.
