1.Institute of Mathematics,University of Zurich,Zurich,Switzerland;2.Gran Sasso Science Institute,L’Aquila,Italy;3.Dipartimento di Matematica G. Castelnuovo,Sapienza Università di Roma,Roma,Italy
Abstract:
We consider a quantum particle interacting with N obstacles, whose positions are independently chosen according to a given probability density, through a two-body potential of the form N2V (Nx) (Gross-Pitaevskii potential). We show convergence of the N dependent one-particle Hamiltonian to a limiting Hamiltonian where the quantum particle experiences an effective potential depending only on the scattering length of the unscaled potential and the density of the obstacles. In this sense our Lorentz gas model exhibits a universal behavior for N large. Moreover we explicitely characterize the fluctuations around the limit operator. Our model can be considered as a simplified model for scattering of slow neutrons from condensed matter.