Zero-Bias Conductance Through Side-Coupled Double Quantum Dots
  Low temperature zero-bias conductance through two side-coupled quantum dots is investigated using Wilson's numerical renormalization group technique. A low-temperature phase diagram is computed. Near the particle-hole symmetric point localized electrons form a spin-singlet associated with weak conductance. For weak inter-dot coupling we find enhanced conductance due to the two-stage Kondo effect when two electrons occupy quantum dots. When quantum dots are populated with a single electron, the system enters Kondo regime with enhanced conductance. Analytical expressions for the width of the Kondo regime and the Kondo temperature in this regime are given. 
J. Bonca, R. Zitko