Calculation of the current noise spectrum in mesoscopic transport: an efficient quantum master equation approach

Based on our recent work on quantum transport [Li et al., Phys. Rev. B 71, 205304 (2005)], where the calculation of transport current by means of quantum master equation was presented, in this paper we show how an efficient calculation can be performed for the transport noise spectrum. Compared to the longstanding classical rate equation or the recently proposed quantum trajectory method, the approach presented in this paper combines their respective advantages, i.e., it enables us to tackle both the many-body Coulomb interactionand quantum coherence on equal footing and under a wide range of setup circumstances. The practical performance and advantages are illustrated by a number of examples, where besides the known results and new insights obtained in a transparent manner, we find that this alternative approach is much simpler than other well-known full quantum mechanical methods such as the Landauer-B"uttiker scattering matrix theory and the nonequilibrium Green’s function technique.