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arXiv · 1905.12050

Coupled-cluster impurity solvers for dynamical mean-field theory

Tianyu Zhu·Carlos A. Jimenez-Hoyos·James McClain·Timothy C. Berkelbach·Garnet Kin-Lic Chan
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Abstract

We describe the use of coupled-cluster theory as an impurity solver in dynamical mean-field theory (DMFT) and its cluster extensions. We present numerical results at the level of coupled-cluster theory with single and double excitations (CCSD) for the density of states and self-energies of cluster impurity problems in the one- and two-dimensional Hubbard models. Comparison to exact diagonalization shows that CCSD produces accurate density of states and self-energies at a variety of values of $U/t$ and filling fractions. However, the low cost allows for the use of many bath sites, which we define by a discretization of the hybridization directly on the real frequency axis. We observe convergence of dynamical quantities using approximately 30 bath sites per impurity site, with our largest 4-site cluster DMFT calculation using 120 bath sites. We suggest coupled cluster impurity solvers will be attractive in ab initio formulations of dynamical mean-field theory.

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Tianyu Zhu, Carlos A. Jimenez-Hoyos, James McClain, Timothy C. Berkelbach, Garnet Kin-Lic Chan. 2019-08-19. Coupled-cluster impurity solvers for dynamical mean-field theory. https://doi.org/10.1103/physrevb.100.115154

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