Abstract
We calculate the renormalized parameters for the quasiparticles and their interactions for the Hubbard model in the paramagnetic phase as deduced from the low-energy Fermi-liquid fixed point using the results of a numerical renormalization-group calculation (NRG) and dynamical mean-field theory (DMFT). Even in the low-density limit there is significant renormalization of the local quasiparticle interaction , in agreement with estimates based on the two-particle scattering theory of J. Kanamori [Prog. Theor. Phys. 30, 275 (1963)]. On the approach to the Mott transition we find a finite ratio for , where is the renormalized bandwidth, which is independent of whether the transition is approached by increasing the on-site interaction or on increasing the density to half filling. The leading term in the self-energy and the local dynamical spin and charge susceptibilities are calculated within the renormalized perturbation theory (RPT) and compared with the results calculated directly from the NRG-DMFT. We also suggest, more generally from the DMFT, how an approximate expression for the spin susceptibility can be derived from repeated quasiparticle scattering with a local renormalized scattering vertex.
12 More- Received 9 August 2016
- Revised 14 November 2016
DOI:https://doi.org/10.1103/PhysRevB.94.195152
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