Non-equilibrium noise in low-dimensional systems

The transmission coefficient of a thin disordered wire varies dramatically with the energy of electrons attempting to diffuse along the wire. Hence on a microscopic scale the relationship between current and voltage is a highly nonlinear one. This results in noise, in the form of harmonic and intermodulation distortion of the input signal, which has a l/f 2 behaviour up to frequencies where hf is comparable with k B T. Analytic expressions are derived for the noise in the limit of weak disorder.