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 cu rrent and shot noise are shown to be sensitive to the parity of the el ectron number on the grain. In particular, tunneling may cross over fr om pair channels to two distinct single-particle channels at finite vo ltage. The two corresponding threshold voltages are sensitive to the c ircuit parameters. While it is difficult to identify them from the I-V curve, they can be determined from the normalized zero-frequency nois e and the finite-frequency noise spectrum.