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Natural-orbital impurity solver and projection approach for Green's functions

We extend a previously proposed rotation and truncation scheme to optimize quantum Anderson impurity calculations with exact diagonalization [Y. Lu, M. Höppner, O. Gunnarsson, and M. W. Haverkort, Phys. Rev. B 90, 085102 (2014)] to density-matrix renormalization group (DMRG) calculations. The metho...

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Hauptverfasser: Lu, Yi (VerfasserIn) , Cao, X. (VerfasserIn) , Hansmann, P. (VerfasserIn) , Haverkort, Maurits W. (VerfasserIn)
Dokumenttyp: Article (Journal)
Sprache:Englisch
Veröffentlicht: 16 September 2019
In: Physical review
Year: 2019, Jahrgang: 100, Heft: 11
ISSN:2469-9969
DOI:10.1103/PhysRevB.100.115134
Online-Zugang:Verlag, Volltext: https://doi.org/10.1103/PhysRevB.100.115134
Verlag: https://link.aps.org/doi/10.1103/PhysRevB.100.115134
Volltext
Verfasserangaben:Y. Lu, X. Cao, P. Hansmann, and M.W. Haverkort
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Zusammenfassung:We extend a previously proposed rotation and truncation scheme to optimize quantum Anderson impurity calculations with exact diagonalization [Y. Lu, M. Höppner, O. Gunnarsson, and M. W. Haverkort, Phys. Rev. B 90, 085102 (2014)] to density-matrix renormalization group (DMRG) calculations. The method reduces the solution of a full impurity problem with virtually unlimited bath sites to that of a small subsystem based on a natural impurity orbital basis set. The later is solved by DMRG in combination with a restricted-active-space truncation scheme. The method allows one to compute Green's functions directly on the real frequency or time axis. We critically test the convergence of the truncation scheme using a one-band Hubbard model solved in the dynamical mean-field theory. The projection is exact in the limit of both infinitely large and small Coulomb interactions. For all parameter ranges, the accuracy of the projected solution converges exponentially to the exact solution with increasing subsystem size.
Beschreibung:Gesehen am 26.02.2020
Beschreibung:Online Resource
ISSN:2469-9969
DOI:10.1103/PhysRevB.100.115134

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