Level fluctuations and many-body effects in disorder-free quantum dots

We have investigated whether many-body effects can induce significant level fluctuations in a disorder-free quantum dot. The closed energy shell struc tures and relaxation of the Hartree-Fock (HF) potentials are found to play a significant role. The level degeneracy consistent with the rotational sym metry of the confining potential determines the structure of the energy she lls. A closed shell state of a dot can give rise to large fluctuations. Whe n a strong magnetic field is present the shell structure is absent and fluc tuations are significantly reduced.