  The current noise spectrum of a single-electron transistor (SET) coupled to a
nano-mechanical resonator is calculated in the classical regime. Correlations
between the charge on the SET island and the position of the resonator give
rise to a distinctive noise spectrum which can be very different from that of
the uncoupled SET. The current noise spectrum of the coupled system contains
peaks at both the frequency of the resonator and double the resonator
frequency, as well as a strong enhancement of the zero-frequency noise. The
heights of the peaks are controlled by the strength of the coupling between the
SET and the resonator, the damping of the resonator, and the temperature of the
system.
