Multi-orbital simplified parquet equations for strongly correlated electrons

Abstract

We extend an approximation earlier developed by us for the single-impurity Anderson model to a full-size impurity solver for models of interacting electrons with multiple orbitals. The approximation is based on parquet equations simplified by separating small and large energy fluctuations justified in the critical region of a pole in the two-particle vertex. We show that an $l$-orbital model with most general interaction is described within this approximation by $4l^2\times 4l^2$ matrices and is Fermi liquid in the metallic phase. We explicitly calculate properties of a paramagnetic solution of a two-orbital Hubbard model with a Hund exchange and orbital splitting within the dynamical mean-field approximation. We trace the genesis of a metal-insulator transition induced by a crystal field and vanishing of the Kondo quasiparticle peak in strongly correlated orbitally asymmetric systems.

14 pages, 15 figures

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Cited by in corpus (8)

• Efficient implementation of the parquet equations -- role of the reducible vertex function and its kernel approximation
• Solving the Parquet Equations for the Hubbard Model beyond Weak Coupling
• Multiscale space-time ansatz for correlation functions of quantum systems based on quantics tensor trains
• Build-up of the Kondo effect from real-time 2PI effective action for the Anderson impurity model
• Competition between antiferromagnetic and charge density wave fluctuations in the extended Hubbard model
• Development of an efficient impurity solver in dynamical mean field theory for multi-band systems: The iterative perturbation theory combined with the parquet equations
• Simplification of the local full vertex in the impurity problem in DMFT and its applications for the nonlocal correlation
• Improvement of the simplification method for the local two-particle full-vertex towards precise frequency behavior