@article{oai:niigata-u.repo.nii.ac.jp:00001971, author = {Hewson, A. C. and Bradley, S. and Bulla, R. and Ono, Y.}, issue = {19-20}, journal = {International Journal of Modern Physics. B, Condensed matter physics, statistical physics, applied physics, International Journal of Modern Physics. B, Condensed matter physics, statistical physics, applied physics}, month = {Dec}, note = {In recent years the numerical renormalization group (NRG) method has been extended to the calculation of dynamic response functions and transport properties of magnetic impurity models. The approach can now be applied more widely to lattice models of strongly correlated electron systems by the use of dynamical mean field theory (DMFT), in which the lattice problem is transformed into one for an e ective impurity with an additional self-consistency constraint. We review these developments and assess the potential for further applications of this approach. We also discuss an alternative approach to renormalization, renormalized perturbation theory, in which the leading asymptotically exact results for the low temperature regime for a number of magnetic impurity models can be obtained within nite order perturbation theory.}, pages = {2549--2567}, title = {Renormalization Group Approaches to Strongly Correlated Electron Systems}, volume = {15}, year = {2001} }