Crossover from Anderson- to Kondo-like behavior: Universality induced by   spin-charge separation
  The thermodynamics of a lattice regularized asymmetric Anderson impurity in a correlated host is obtained by an exact solution. The crossover from the Anderson- to the Kondo-regime is studied, thus making contact with predictions by scaling theory. On the basis of the exact solution, the transition to universal Kondo behavior is shown to be realized by a graduate separation of the energy scales of spin and charge excitations. 
Michael Bortz, Andreas Kl\"umper and Christian Scheeren