A triple quantum dot in a single wall carbon nanotube
  A top-gated single wall carbon nanotube is used to define three coupled quantum dots in series between two electrodes. The additional electron number on each quantum dot is controlled by top-gate voltages allowing for current measurements of single, double and triple quantum dot stability diagrams. Simulations using a capacitor model including tunnel coupling between neighboring dots captures the observed behavior with good agreement. Furthermore, anti-crossings between indirectly coupled levels and higher order cotunneling are discussed. 
K. Grove-Rasmussen, H. I. J{\o}rgensen, T. Hayashi, P. E. Lindelof,   and T. Fujisawa