# First-Principles Determination of Electron-Ion Couplings in the Warm Dense Matter Regime

## TL;DR

This paper introduces a first-principles method using a Kubo relation to accurately calculate electron-ion energy exchange rates in warm dense matter, accounting for complex quantum and strong coupling effects.

## Contribution

It develops a novel, self-consistent Kubo-based approach for determining electron-ion couplings applicable to diverse materials in extreme conditions.

## Key findings

- Results align with experimental data for aluminum and copper.
- The method captures non-linear and strong coupling effects.
- Provides a unified framework for different materials.

## Abstract

We present first-principles calculations of the rate of energy exchanges between electrons and ions in nonequilibrium warm dense plasmas, liquid metals and hot solids, a fundamental property for which various models offer diverging predictions. To this end, a Kubo relation for the electron-ion coupling parameter is introduced, which includes self-consistently the quantum, thermal, non-linear and strong coupling effects that coexist in materials at the confluence of solids and plasmas. Most importantly, like other Kubo relations widely used for calculating electronic conductivities, the expression can be evaluated using quantum molecular dynamics simulations. Results are presented and compared to experimental and theoretical predictions for representative materials of various electronic complexity, including aluminum, copper, iron and nickel.