A Stochastic approach to thermal DFT

ORAL

Abstract

Despite progress in observational astronomy, some elements such as the internal composition of planets are still not well-understood. A root cause is our limited understanding of matter under extreme conditions (MEC) - pressures in the GPa-TPa range and temperatures (T) up to 105 K. Due to the difficulty in preparing MECs, the experimental input is limited, and ab initio calculations are sometimes the only source of information. The Kohn-Sham density functional theory (KS-DFT) seems as a reliable and useful tool for obtaining information on MEC. Calculations in finite temperatures, however, are expensive due to the large number of fractionally occupied KS orbitals involved. A stochastic method developed recently[1],[2], appears to be a fitting approach to this problem. By performing a stochastic trace, the KS Hamiltonian is directly obtained from the density, resulting in a scaling of O(T-1).
I will introduce the convergence and errors involved in calculations of the canonical free energy. In addition, a stochastic approach to calculate the Kubo-Greenwood conductivity will be presented.


[1] R. Baer, D. Neuhauser, E. Rabani, Phys. Rev. Lett. 111, 106402 (2013)

[2]Yael Cytter, Eran Rabani, Daniel Neuhauser, and Roi Baer Phys. Rev. B 97, 115207 (2018)

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Presenters

  • Yael Cytter

    Department of Chemistry, Fritz Haber Center for Molecular Dynamics, Hebrew University of Jerusalem, Israel, Chemistry, Fritz Haber Center for Molecular Dynamics, Hebrew University of Jerusalem, Israel

Authors

  • Yael Cytter

    Department of Chemistry, Fritz Haber Center for Molecular Dynamics, Hebrew University of Jerusalem, Israel, Chemistry, Fritz Haber Center for Molecular Dynamics, Hebrew University of Jerusalem, Israel

  • Daniel Neuhauser

    Department of Chemistry and Biochemistry, University of California Los Angeles, USA, Chemistry and Biochemistry, UC Los Angeles

  • Eran Rabani

    Department of Chemistry, University of California Berkeley and Lawrence Berkeley National Laboratory, USA, Chemistry, University of California and Lawrence Berkeley National Laboratory, USA, College of Chemistry, UC Berkeley

  • Roi Baer

    Department of Chemistry, Fritz Haber Center for Molecular Dynamics, Hebrew University of Jerusalem, Israel, Chemistry, Fritz Haber Center for Molecular Dynamics, Hebrew University of Jerusalem, Israel, Chemistry, Hebrew University (Israel)