Hillert Materials Modeling Colloquium series III: More-predictive density functionals, symmetry breaking, and strong correlation
Professor John P. Perdew is a developer of first-principles density functional theory for atoms, molecules, and solids. The wide use of this theory in physics, chemistry, and materials science has made him one of the most-cited physicists in the world. In this seminar he will focus on the exact density functional for the exchange-correlation energy.
Time: Tue 2022-05-10 15.00
Location: Zoom
Video link: https://kth-se.zoom.us/j/64401095435
Language: English
Participating: Professor John P. Perdew
Approximate density functionals constructed to satisfy known mathematical properties of the exact density functional for the exchange-correlation energy of a many-electron system can be predictive over a wide range of materials and molecules. The strongly constrained and appropriately normed (SCAN) meta generalized gradient approximation satisfies 17 exact constraints, and nicely describes some systems that were formerly thought to be beyond the reach of density functional theory, such as the cuprates. In some cases (e.g., barrier heights to chemical reactions and hydrogen bonds in water), SCAN is dramatically more accurate when evaluated on the Hartree-Fock density than it is on its own self-consistent and more delocalizing density.
Ground states that break the symmetry of a Coulomb-interacting Hamiltonian can be understood as dynamic density or spin density fluctuations that drop to low or zero frequency and so persist over long times. In many cases, symmetry breaking transforms the strong correlation in a symmetry-unbroken wave function into moderate correlation like that found in the uniform electron gas of high or valence-electron density (an “appropriate norm” for constraint-based approximations).
Hillert Materials Modeling Colloquium Series is arranged by Hillert Modeling Laboratory
Department of Materials Science and Engineering
KTH Royal Institute of Technology
Spokesperson: