Mesoscopic fluctuations of elastic cotunneling

We study mesoscopic fluctuations of the conductance through a quantum dot at the wings of the Coulomb blockade peaks. At low temperatures, the main mechanism of conduction is elastic cotunneling. The conductance strongly fluctuates with an applied magnetic field. The magnetic correlation field is shown to be controlled by the charging energy, and the correlation function has a universal form. The distribution function for the conductance obtained analytically shows a nontrivial crossover between the orthogonal and unitary ensembles.