ABSTRACT
In the previous chapters, the single tunnel junction in Coulomb blockade was modeled essentially as a charged (or charging) capacitor. Singleelectron tunneling as a Dirac delta pulse. This picture can be extended to more junctions. Therefore, consider a two tunnel junction circuit in Coulomb blockade. The two capacitors create an island in the circuit, that is, a part of the circuit between the two capacitors is electrically isolated from the circuit. If we allow the possibility that one or more electrons had been tunneled through only one of the junctions then the total net charge of the island and its environment will be nonzero and opposite.
