Berlin 2024 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 80: Correlated Electrons: Poster
TT 80.48: Poster
Thursday, March 21, 2024, 15:00–18:00, Poster E
Green’s functions of quantum impurity systems from MPS-based band Lanczos — •Coraline Letouzé1, Guillaume Radtke1, Benjamin Lenz1, and Sebastian Paeckel2 — 1Sorbonne Université, Muséum National d’Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, 75005 Paris, France — 2Department of Physics, Arnold Sommerfeld Center for Theoretical Physics (ASC), Munich Center for Quantum Science and Technology (MCQST), Ludwig-Maximilians-Universität München, 80333 München, Germany
Quantum impurity models are important both on their own (see e.g. Kondo effect or quantum dots) and as solvers for embedding techniques such as the dynamical mean-field theory (DMFT). Accurately calculating the Green’s functions of such interacting quantum many-body systems is still a challenging problem. To that aim, we implement the (band) Lanczos algorithm for matrix-product states (MPS). It allows us to compute real-frequency Green’s functions by diagonalizing the Krylov projection of the Hamiltonian, while efficiently compressing the many-body wavefunctions. We present results for the 2D Hubbard model and DMFT-based impurity models of transition metal oxides.
Keywords: Matrix-product states; Lanczos algorithm; Impurity solver; Hubbard model; Dynamical mean-field theory