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Center for Nonlinear Studies |
The rapidly growing ability to form and probe warm dense matter conditions increases the demand for a quantitative predictive modeling of the fast and highly nonequilibrium processes induced in the target materials.In particular, much uncertainty remains in our understanding of the electron-ion energy relaxation timescales as illustrated by the strongdisagreements between analytical models and indicated by recent experimental investigations.This reflects both the scarcity of accurate experimental measurements as well as the difficulty of performing first-principle calculations of out-of-equilibrium processes in the warm dense matter regime.In this work we present the first ab-initio calculations of the electron-ion energy relaxation rates (a.ka. couplings) in warm dense matter.To this end, we derived a Kubo relation for the electron-ion couplings and developed methods to compute the Kubo relation with quantummolecular dynamics techniques.We discuss the results obtained for several materials of practical and academic interest (including Aluminum, Hydrogen, Copper, and Iron)across a range of conditions of temperature and density, including the solid and liquid metal conditions traversed in warm dense matterexperiments.Our approach serves as a very useful comparison with the experimental measurements and model predictions, permits an extension into densitiesand temperatures not covered by the experiments, and provides insight into the underlying physics.
Host: Arvind T. Mohan