Kondo physics of the Anderson impurity model by Distributional Exact Diagonalization
arXiv:1608.02434 · doi:10.1103/PhysRevB.94.235133
Abstract
The Distributional Exact Diagonalization (DED) scheme is applied to the description of Kondo physics in the Anderson impurity model. DED maps Anderson's problem of an interacting impurity level coupled to an infinite bath onto an ensemble of finite Anderson models, each of which can be solved by exact diagonalization. An approximation to the self-energy of the original infinite model is then obtained from the ensemble averaged self-energy. Using Friedel's sum rule, we show that the particle number constraint, a central ingredient of the DED scheme, ultimately imposes Fermi liquid behavior on the ensemble averaged self-energy, and thus is essential for the description of Kondo physics within DED. Using the Numerical Renormalization Group (NRG) method as a benchmark, we show that DED yields excellent spectra, both inside and outside the Kondo regime for a moderate number of bath sites. Only for very strong correlations () does the number of bath sites needed to achieve good quantitative agreement become too large to be computationally feasible.
10 pages, 6 figures; replaced with revised manuscript
References in corpus (8)
- Continuous-time Monte Carlo methods for quantum impurity models
- The numerical renormalization group method for quantum impurity systems
- Energy resolution and discretization artefacts in the numerical renormalization group
- Kondo effect in single atom contacts: the importance of the atomic geometry
- Towards a full ab initio theory of strong electronic correlations in nanoscale devices
- Conserving approximations in direct perturbation theory: new semianalytical impurity solvers and their application to general lattice problems
- Signatures of coherent electronic quasiparticles in the paramagnetic Mott insulator
- Variational exact diagonalization method for Anderson impurity models