FM 08-15; arXiv:1507.05678

Authors : Giovanni Gallavotti, Ian Jauslin

Title: Kondo effect in the hierarchical s-d model

Abstract: The s - d model describes a chain of spin-1/2 electrons interacting magnetically with a two-level impurity. It was introduced to study the Kondo effect, in which the magnetic susceptibility of the impurity remains finite in the 0-temperature limit as long as the interaction of the impurity with the electrons is anti-ferromagnetic. A variant of this model was introduced by Andrei, which he proved was exactly solvable via Bethe Ansatz. A hierarchical version of Andrei's model was studied by Benfatto and the authors. In the present letter, that discussion is extended to a hierarchical version of the s - d model. The resulting analysis is very similar to the hierarchical Andrei model, though the result is slightly simpler.

Keywords: Renormalization group; Non-perturbative renormalization; Kondo effect; Fermionic hierarchical model; Quantum field theory

Giovanni Gallavotti
INFN Fisica, Rutgers University e Accademia dei Lincei
Universita di Roma Sapienza, 00185 Roma, Italy

Ian Jauslin
University of Rome Sapienza, 00185 Roma, Italy

Supplementary material: The computation of the flow equation for the hierarchical Kondo model can be carried out using the meankondo program, available from