  Based on our recently developed quantum transport theory in term of an exact
master equation, the corresponding particle-number resolved ($n$-resolved)
master equation and the related shot noise spectrum formalism covering the full
frequency range are constructed. We demonstrate that the noise spectra of
transport current through single quantum dot and double quantum dots show
characteristic steps and/or peak-dips in different tunneling frequency regimes
through tuning the applied bias voltage and/or gate voltage at low
temperatures. The peak-dips crossing the tunneling resonant frequencies is a
combination effect of non-Markovian and cotunneling processes. These
voltage-dependent tunneling resonance characteristics can be utilized to
effectively modulate the internal Rabi resonance signature in the noise
spectrum.
