---

The inclusion of charging and spin-exchange interactions within the Universal Hamiltonian description of quantum dots is a highly non-trivial problem owing to the fact that it leads to a formulation of the problem in terms of a non-Abelian action. We present an exact analytical solution of the problem, in particular, in the vicinity of the Stoner instability point. We calculate exactly several physical observables, including the tunneling density of states (TDOS) and the spin susceptibility. We find that due to the presence of spin-exchange interaction, at the vicinity of the instability point the TDOS exhibits a non-monotonous behavior as function of the tunneling energy. This effect survives even at temperatures much higher than the exchange energy. Also, we find that in the same temperature range the single-particle level fluctuations enhances the spin-susceptibility in the vicinity of the Stoner instability. Experimentally, our results could be tested in nearly ferromagnetic materials. Some of the results are published in I.S. Burmistrov, Yu. Gefen, M.N. Kiselev, JETP Lett. 92, 766 (2010).

---

Dr. Igor Burmistrov, Landau Institute for Theoretical Physics, Moscow
Seminarraum Theoretische Physik
Contact: not specified