Sum-rule conserving spectral functions from the numerical renormalization group |
| |
Authors: | Weichselbaum Andreas von Delft Jan |
| |
Institution: | Physics Department, Arnold Sommerfeld Center for Theoretical Physics, and Center for NanoScience, Ludwig-Maximilians-Universit?t München, D-80333 München, Germany. |
| |
Abstract: | We show how spectral functions for quantum impurity models can be calculated very accurately using a complete set of discarded numerical renormalization group eigenstates, recently introduced by Anders and Schiller. The only approximation is to judiciously exploit energy scale separation. Our derivation avoids both the overcounting ambiguities and the single-shell approximation for the equilibrium density matrix prevalent in current methods, ensuring that relevant sum rules hold rigorously and spectral features at energies below the temperature can be described accurately. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|