Fermi-liquid regime of the mesoscopic Kondo problem

We consider the low temperature regime of the mesoscopic Kondo problem, and in particular the relevance of a Fermi-liquid description of this regime. Using two complementary approaches – a mean field slave fermion approximation on the one hand and a Fermi-liquid description “`a la Nozi`eres” supplemented by an argument of separation of scale on the other hand – we show that they both lead to (essentially) the same quasi-particle spectra, providing in this way a strong indication that they both give the correct physics of this regime.