Quantum discreteness and fundamental 1/f noise in tunnel junctions,   nano-composites and other many-electron systems
  It is shown, with citing tunnel junction as an example, that mutual interplay of electron quantum transfers in a conducting system can be the fast mechanism for generation fundamental low-frequency flicker conductance fluctuations (1/f noise) without composing Lorentzians. This effect is lost in a theory which neglects the actual discreteness of electron energy levels. The analytical estimates of fluctuations of tunnel conductance are obtained, and the strong 1/f-noise sensibility to the discreteness as observed in nano-composites is explained both qualitatively and quantitatively. 
Yu. E. Kuzovlev, Yu. V. Medvedev and A. M. Grishin