Self-energy embedding theory (SEET)

I will present a discussion of 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 have applied SEET to both molecular and periodic examples where commonly our chosen subsystem is 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. We list all the intricacies for one of the possible procedures while focusing our discussion on many practical implementation aspects such as the choice of best orbital basis, impurity solver, and many steps necessary to reach high accuracy.
Finally, on a set of carefully chosen molecular and periodic examples, we demonstrate that SEET, which is a controlled, systematically improvable Green's function method can be as accurate as established wavefunction quantum chemistry methods.