Interaction effects on the conductance peak height statistics in quantum dots

A random interaction matrix model is used to study the statistics of conductance peak heights in Coulomb blockade quantum dots. The model contains a parameter U that measures the fluctuation width of the interaction matrix elements. When the single-particle dynamics conserve time-reversal symmetry, the peak height distribution is insensitive to U and is described by the experimentally observed orthogonal statistics. But when the single-particle dynamics break time-reversal symmetry, the peak height statistics exhibit a crossover from unitary to orthogonal symmetry at large values of U. For values of U that are smaller than the single-particle mean-level spacing, the peak height distribution remains close to the distribution described by the unitary symmetry, in agreement with the experiments.