We present an ab initio numerical many-body GW calculation of the band plot in freestanding graphene. We consider the full ionic and electronic structure introducing e-e interaction and correlation effects via a self-energy containing non-Hermitian and dynamical terms. With respect to the density-functional theory local-density approximation, the Fermi velocity is renormalized with an increase ...

This paper is devoted to study many-body effects in the positron annihilation experiment, both electron−positron (e–p) and electron–electron (e–e) correlations. Various theories of the e–p interaction in real solids were used to verify them by comparing theoretical and experimental e–p momentum densities in Cu and Y. We show that the lattice potential has an essential influence on the e–p corre...

Motivated by the intriguing physics of quasi-two-dimensional fermionic systems, such as high-temperature superconducting oxides, layered transition metal chalcogenides, or surface interface development many-body computational methods geared at including both local and nonlocal electronic correlations has become a rapidly evolving field. It been realized, however, that success can be hampered em...