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

Lu Y, Cao X, Hansmann P, Haverkort MW (2019)


Publication Type: Journal article

Publication year: 2019

Journal

Book Volume: 100

Article Number: 115134

Journal Issue: 11

DOI: 10.1103/PhysRevB.100.115134

Abstract

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)PRBMDO1098-012110.1103/PhysRevB.90.085102] 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.

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APA:

Lu, Y., Cao, X., Hansmann, P., & Haverkort, M.W. (2019). Natural-orbital impurity solver and projection approach for Green's functions. Physical Review B, 100(11). https://doi.org/10.1103/PhysRevB.100.115134

MLA:

Lu, Y., et al. "Natural-orbital impurity solver and projection approach for Green's functions." Physical Review B 100.11 (2019).

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