期刊
PHYSICAL REVIEW B
卷 98, 期 23, 页码 -出版社
AMER PHYSICAL SOC
DOI: 10.1103/PhysRevB.98.235151
关键词
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资金
- Deutsche Forschungsgemeinschaft (DFG) [FOR 1346]
- Swiss National Science Foundation [200021-165539]
- JSPS KAKENHI [16H01064, 18H04301, 16K17735]
- European Research Council through ERC [724103]
- DFG [Ho2422/10-1, HO2422/11-1]
- DFG research training group 1995 Quantum Many-Body Methods in Condensed Matter Systems
- Swiss National Science Foundation (SNF) [200021_165539] Funding Source: Swiss National Science Foundation (SNF)
We check the accuracy of the constrained random phase approximation (cRPA) downfolding scheme by considering one-dimensional two- and three-orbital Hubbard models with a target band at the Fermi level and one or two screening bands away from the Fermi level. Using numerically exact quantum Monte Carlo simulations of the full and downfolded model, we demonstrate that depending on filling, the effective interaction in the low-energy theory is either barely screened or antiscreened, in contrast to the cRPA prediction. This observation is explained by a functional renormalization group analysis, which shows that the cRPA contribution to the screening is to a large extent canceled by other diagrams in the direct particle-hole channel. We comment on the implications of this finding for the ab initio estimation of interaction parameters in low-energy descriptions of solids.
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