NMR in a System of Small Metallic Particles: A Novel Mesoscopic Phenomenon

We consider the NMR line shape for a system of small metal particles. The problem is reduced to calculation of the local density of states distribution function. We present the first exact calculation of this quantity for the mesoscopic system. Using the super-symmetry method, we calculated exactly the whole distribution function which gives the resonance-line shape. It turns out that at low temperatures, the line becomes very broad and asymmetric. The Knight shift defined as the maximum of the line decreases when decreasing the temperature. We found a good agreement of our results with a few experiments done long ago.