Quasi-Langevin method for shot noise calculation in single-electron tunneling

It is shown that quasi-Langevin method can be used for the calculation of the shot noise in correlated single-electron tunneling. We generalize the existing Fokker-Plank-type approach and show its equivalence to quasi-Langevin approach. The advantage of the quasi-Langevin method is a natural possibility to describe simultaneously the high (``quantum'') frequency range.Comment: 13 pages (RevTeX), 1 figur