  We introduce a generic approach to study interaction effects in diffusive or
chaotic quantum dots in the Coulomb blockade regime. The randomness of the
single-particle wave functions induces randomness in the two-body interaction
matrix elements. We classify the possible induced two-body ensembles, both in
the presence and absence of spin degrees of freedom. The ensembles depend on
the underlying space-time symmetries as well as on features of the two-body
interaction. Confining ourselves to spinless electrons, we then use the
Hartree-Fock (HF) approximation to calculate HF single-particle energies and HF
wave functions for many realizations of the ensemble. We study the statistical
properties of the resulting one-body HF ensemble for a fixed number of
electrons. In particular, we determine the statistics of the interaction matrix
elements in the HF basis, of the HF single-particle energies (including the HF
gap between the last occupied and the first empty HF level), and of the HF
single-particle wave functions. We also study the addition of electrons, and in
particular the distribution of the distance between successive conductance
peaks and of the conductance peak heights.
