  A detailed study of the low-temperature physics of an interacting double
quantum dot system in a T-shape configuration is presented. Each quantum dot is
modeled by a single Anderson impurity and we include an inter-dot
electron-electron interaction to account for capacitive coupling that may arise
due to the proximity of the quantum dots. By employing a numerical
renormalization group approach to a multi-impurity Anderson model, we study the
thermodynamical and transport properties of the system in and out of the Kondo
regime. We find that the two-stage-Kondo effect reported in previous works is
drastically affected by the inter-dot Coulomb repulsion. In particular, we find
that the Kondo temperature for the second stage of the two-stage-Kondo effect
increases exponentially with the inter-dot Coulomb repulsion, providing a
possible path for its experimental observation.
