Green's function formulation of quantum defect embedding theory*

We present a Green’s function formulation of the quantum defect embedding theory (QDET) where a double counting scheme is rigorously derived within the G₀W₀ approximation [1]. We show the robustness of our methodology by applying the theory with the newly derived double counting scheme to several defects in diamond. We discuss a strategy to obtain converged results as a function of the size and composition of the active space. The results show that QDET, as implemented in the WEST code (http://west-code.org), is a promising approach to investigate strongly correlated states of defects in solids. Finally, we discuss how to carry-out QDET calculations on GPUs [2] and noisy intermediate-scale quantum computers [3]. 

[1] N. Sheng, C. Vorwerk, M. Govoni, G. Galli, J. Chem. Theory Comput. 18, 3512 (2022).

[2] V. Yu, M. Govoni, J. Chem. Theory Comput. 18, 4690 (2022).

[3] B. Huang, M. Govoni, G. Galli, PRX Quantum 3, 010339 (2022).