Non-Markovian full counting statistics of cotunneling assisted sequential tunneling in open quantum systems

We develop a non-Markovian full counting statistics formalism taking into account both the sequential tunneling and cotunneling based on the exact particle number resolved time-convolutionless master equation and the Rayleigh-Schr\"{o}dinger perturbation theory. Then, we study the influences of the quantum coherence and the cotunneling assisted sequential tunneling processes on the non-Markovian full counting statistics of electron tunneling through an open quantum system, which consists of a side-coupled double-quantum-dot molecule weakly coupled to two electron reservoirs. We demonstrate that in the sequential tunneling regime the competition or interplay between the quantum coherence and the cotunneling processes determines whether the super-Poissonian of the shot noise, the skewness and the kurtosis take place and whether the sign transitions of the values of the skewness and the kurtosis occur in the strong quantum-coherent side-coupled double-quantum-dot molecule. These results suggest that it is necessary to consider the effects of the quantum coherence and the cotunneling processes on the full counting statistics of electron tunneling through open strong quantum-coherent quantum systems in the sequential tunneling regime, which provide a deeper insight into understanding of electron tunneling through open quantum systems.