Classical theory for shot noise in resonant tunneling

We show that shot noise for electrons can be suppressed in resonant tunneling through a double barrier, using a classical description based on the rate equation for ``sequential'' tunneling. The suppression is greatest when the escape rates through the two barriers are equal, in agreement with experiment and with the quantum-mechanical ``coherent'' model of resonant tunneling. A master equation is needed to calculate the noise, but cannot be uniquely derived from the rate equation; choices differ in the way that they describe transport between the emitter and the resonant state. Our choice for the rates, which are consistent with the exclusion principle, gives a suppression of the shot noise. We briefly discuss the results of choosing rates that are consistent with classical or Bose statistics instead of Fermi statistics. Finally, we apply our results to the two-state regime of the classical Coulomb blockade.