Mott physics and collective modes: An atomic approximation of the four-particle irreducible functional

Article

关键词: MEAN-FIELD THEORY;    HUBBARD-MODEL;    ELECTRON-SYSTEMS;    DIMENSIONS;    FLUCTUATIONS;    TRANSITION;    SPIN;   

DOI  :  10.1103/PhysRevB.94.075159

来源: SCIE

【 摘 要 】

We discuss a generalization of the dynamical mean field theory (DMFT) for strongly correlated systems close to a Mott transition based on a systematic approximation of the fully irreducible four-point vertex. It is an atomic-limit approximation of a functional of the one-and two-particle Green functions, built with the second Legendre transform of the free energy with respect to the two-particle Green function. This functional is represented diagrammatically by four-particle irreducible (4PI) diagrams. Like the dynamical vertex approximation (D Gamma A), the fully irreducible vertex is computed from a quantum impurity modelwhose bath is self-consistently determined by solving the parquet equations. However, in contrast with D Gamma A and DMFT, the interaction term of the impurity model is also self-consistently determined. The method interpolates between the parquet approximation at weak coupling and the atomic limit, where it is exact. It is applicable to systems with short-range and long-range interactions.

【 授权许可】

Free