Keldysh Approach for Coulomb Blockade in Double-Barrier Structures

We present a theoretical study of two small normal tunnel junctions connected in series and driven by a dc voltage source, using Keldysh's approach for the nonequilibrium state and taking the current continuity into account by adjusting the electrochemical potential µ in the island. The numerical results of the Coulomb Blockade of tunneling conductance show that the lowest order of the tunneling processes can explain the experimental results qualitatively when the tunneling resistance R T is large compared with the resistance quantum R Q = h /2 e 2 .