Kondo resonance in a spinless two-level quantum dot side-coupled to two leads

We study pseudospin Kondo resonance in a spinless two-level quantum dot side-coupled to two leads, which are connected by a direct channel, in the presence of interlevel Coulomb repulsion. We find a mapping of the dot system to a pseudospin Anderson impurity Hamiltonian, which is modified from the conventional one due to the effect of the direct channel. The mapping shows that the Kondo resonance is very sensitive to the direct channel coupling. Based on the equation of motion technique, we discuss the dependence of the Kondo temperature on the coupling of the direct channel.