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ISRN Condensed Matter Physics
Volume 2012 (2012), Article ID 391813, 6 pages
Research Article

Factorization of the -Electron Wave Function in the Kondo Ground State

Department of Physics & Astronomy, University of Southern California, Los Angeles, CA 90089-0484, USA

Received 12 July 2012; Accepted 13 September 2012

Academic Editors: C. Trallero-Giner and V. H. Tran

Copyright © 2012 Gerd Bergmann. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The multielectron wave function of an interacting electron system depends on the size of the system, that is, the number of electrons. Here the question investigated is how the wave function changes for a symmetric Friedel-Anderson impurity when the volume is doubled. It turns out that for sufficiently large volume (when the level spacing is smaller than the resonance width) the change in the wave function can be expressed in terms of a universal single-electron state centered at the Fermi level. This electron state is independent of the number of electrons and independent of the parameters of the Friedel-Anderson impurity. It is even the same universal state for a Kondo impurity and a symmetric Friedel impurity independent of any parameter. The only requirement is that the impurity has a resonance exactly at the Fermi level and that the level spacing is smaller than the resonance width. This result clarifies recent fidelity calculations.