  We investigate the Kondo effect in a double-quantum-dot which is capacitively
coupled to a charge-Qubit. It is shown that due to this capacitive coupling,
the bare inter-dot repulsive interaction in the double-quantum-dot is
effectively reduced and eventually changed to an attractive interaction for
strong couplings between the double-quantum-dot and the Qubit. By deriving the
low-energy effective Hamiltonian of the system, we find that the low energy
dynamics of the system corresponding to these two positive or negative
effective interaction regimes can be described, respectively, by an isotropic
orbital-Kondo or an anisotropic charge-Kondo Hamiltonian. Moreover, we study
various thermodynamic and electronic transport properties of the system by
using the numerical renormalization group method.
