Exchange-correlation effect in the charge response of a warm dense electron gas
Pengcheng Hou, Bao‐Zong Wang, Kristjan Haule, Youjin Deng, Kun Chen
Abstract
The study of warm dense matter, widely existing in nature and laboratories, is challenging due to the interplay of quantum and classical fluctuations. We develop a variational diagrammatic Monte Carlo method and determine the exchange-correlation kernel ${K}_{\mathrm{XC}}(q;T)$ of a warm dense electron gas for a broad range of temperature $T$ and momentum $q$. We observe several interesting physics, including the $T$-dependent evolution of the hump structure and the large-$q$ tail and the emergence of a scaling relation. Particularly, by deriving an analytical form for $q\ensuremath{\rightarrow}\ensuremath{\infty}$, we obtain large-$q$ tails of ${K}_{\mathrm{XC}}$ with high precision. It is shown that the ${K}_{\mathrm{XC}}$ data can be reliably transformed into real space, which can be directly used in density-functional-theory calculations of real warm dense matter.