Exact eigenstates and transmission for two interacting electrons on quantum dots

The eigenstates and the scattering transmission for two interacting electro ns are found exactly for I quantum dots, including the hybridization with t he states on the leads. The results imply limitations on the validity of th e Coulomb blockade picture. The ground states for I = 1, 2 on a one-dimensi onal chain (modeling single and double quantum dots) exhibit quantum deloca lization and magnetic transitions. The effective transmission T of two inte racting electrons through one impurity (I = 1) is enhanced by a renormaliza tion of the repulsive interaction, when one of the electrons is captured in a strongly localized state.