  In this paper, we report stochastic resonance (SR) in a single electron
turnstile. It has been known that SR emerges by the cooperation of a weak
periodic signal and noise in a bistable system. A periodic signal produces
switching between two stable states by lowering the potential barrier. Even if
the amplitude of the signal is not large enough to make the potential barrier
disappear, the switching can occur with the help of noise. As a result, an
output signal-to-noise ratio (SNR), which shows how much the switching is
synchronized with the signal, can be enhanced by increasing the noise. We have
formulated the SR in a single electron turnstile into the adiabatic two-state
theory of McNamara-Wiesenfeld and confirmed its manifestation by numerical
simulation. These results could be applied to detection of the periodic motion
of very small electric charge under noisy environment.
