Ab-initio Quantum Monte Carlo Simulations of Warm Dense Matter

• Applicant: Professor Dr. Michael Bonitz
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: since 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 413245954

This project focuses on the thermodynamic and transport properties of warm dense matter (WDM) – an exotic state on the boarder between solid and plasma. WDM is of fundamental importance for understanding astrophysical objects (giant planets, dwarf stars etc.) as well as for matter under extreme pressure or high excitation. In recent years such states became accessible for experimental investigation in free electron laser facilities, and new diagnostics enabled precise analysis. This poses a challenge to theory and simulation. However, the complex properties of WDM – strong correlations, electronic quantum effects, partial ionization and finite temperatures – allow only for a qualitative description. The use of density functional theory (DFT) has allowed for significant progress in this field, but DFT requires information about the exchange correlation free energy, fXC , of the electrons at finite temperature. In the first phase of this project we could solve this problem. We developed a new path integral Monte Carlo (PIMC) simulation method – permutation blocking PIMC (PB-PIMC) – which allowed us to compute the thermodynamic properties of the electrons exactly. The present proposal aims at continuation of these developments. We plan to extend the simulations to the grand canonical ensemble and to the computation of additional observables, including transport properties, the Matsubara Green function, and the spectral function. Finally, we plan to extend the simulations to hydrogen under WDM conditions. The expected high accuracy of the results will allow us to verify data from earlier models and simulations and, eventually suggest improvements of those approaches. Moreover, we will be able to make accurate predictions for experiments.

• DFG Programme: Research Grants
• Co-Investigator: Dr. Tobias Dornheim