Coulomb blockade peak spacing fluctuations in deformable quantum dots: a further test to Random Matrix Theory

We propose a mechanism to explain the fluctuations of the ground state energy in quantum dots in the Coulomb blockade regime. Employing the random matrix theory we show that shape deformations may change the adjacent peak spacing distribution from Wigner-Dyson to nearly Gaussian even in the absence of strong charging energy fluctuations. We find that this distribution is solely determined by the average number of anti-crossings between consecutive conductance peaks and the presence or absence of a magnetic field. Our mechanism is tested in a dynamical model whose underlying classical dynamics is chaotic. Our results are in good agreement with recent experiments and apply to quantum dots with spin resolved or spin degenerate states.