论文标题
线性响应功能符合沃德 - 塔卡哈西的身份和波动 - 散落定理$ gw $近似
Linear Response Functions Respecting Ward-Takahashi Identity and Fluctuation-Dissipation Theorem within $GW$ Approximation
论文作者
论文摘要
相关电子系统中响应函数的计算是凝结物理学中最重要的问题之一。为了获得物理响应函数，可以保留塔卡哈西的身份和波动散开定理至关重要。在这里，我们在GW框架内提出了一种自吻合的许多身体方法，以根据波动散文定理来计算响应函数，这也满足了沃德 - 塔卡哈西身份。这种方法的有效性在二维一频哈伯德模型上证明了，其中沃德 - 塔卡哈西身份和波动 - 散文定理均经过数值验证。此外，与确定蒙特卡洛方法的准确自旋敏感性相比，从我们的方法获得的结果非常令人满意，并且计算成本大大降低了。
The calculation of response functions in correlated electronic systems is one of the most important problems in the condensed matter physics. To obtain a physical response function, preserving both the Ward-Takahashi identity and the fluctuation-dissipation theorem are crucial. Here we propose a self-consistent many body method within the GW framework to calculate the response functions based on the fluctuation-dissipation theorem, which also satisfies the Ward-Takahashi identity. The validity of this methodology is demonstrated on the two-dimensional one-band Hubbard model, where both the Ward-Takahashi identity and fluctuation-dissipation theorem are verified numerically. Moreover, comparing to the accurate spin susceptibility of the determinantal Monte Carlo approach, the results obtained from our method are quite satisfactory and the computational cost are greatly reduced.
