PARITY-CONTROLLED COULOMB-BLOCKADE EFFECTS IDENTIFIED BY SHOT-NOISE

We develop a microscopic theory for charge transport through a single-electron transistor containing a superconducting grain. Both tunnel current and shot noise are shown to be sensitive to the parity of the electron number on the grain. In particular, tunneling may cross over from pair channels to two distinct single-particle channels at finite voltage. The two corresponding threshold voltages are sensitive to the circuit parameters. While it is difficult to identify them from the I-V curve, they can be determined from the normalized zero-frequency noise and the finite-frequency noise spectrum.