Abstract

Post-DFT Green's function embedding

Dominika Zgid
University of Michigan

I will present a detailed discussion of the methods that we are developing in my group for post-DFT calculations in correlated solids. I will discuss the self-energy embedding theory (SEET) which is a quantum embedding scheme allowing us to describe a chosen subsystem very accurately while keeping the description of the environment at a lower cost. We applied SEET to molecular examples and solids, where our chosen subsystems are made out of a set of strongly correlated orbitals while the weakly correlated orbitals constitute an environment. Such a self-energy separation is very general and to make this procedure applicable to multiple systems a detailed and practical procedure for the evaluation of the system and environment self-energy is necessary.
I will discuss here the importance of the lower level method for weak correlation and will focus on formal aspects of SEET and its connection to Green's function functionals.

Finally, on a set of carefully chosen periodic solids and molecular examples, I will demonstrate that SEET, which is a controlled, systematically improvable Green's function method can be as accurate as established wave function quantum chemistry methods.