Exchange-correlation effect in the charge response of a warm dense electron gas

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, determine the exchange-correlation kernel Kxc(T, q) of a warm dense electron gas for a broad range of temperature T and momentum q, and observe several interesting features like the emergence of a scaling relation. Particularly, by deriving an analytical form for q → ∞, we obtain large-q tails of Kxc with high precision. It is shown that the Kxc data can be reliably transformed into real space, which can be directly used in density-functional-theory calculations of real warm dense matter.