Quantum Fluctuations of a Coulomb Potential as a Source of Flicker Noise

The power spectrum of quantum fluctuations of the electromagnetic field produced by an elementary particle is determined. It is found that in a wide range of practically important frequencies the power spectrum of fluctuations exhibits an inverse frequency dependence. The magnitude of fluctuations produced by a conducting sample is shown to have a Gaussian distribution around its mean value, and its dependence on the sample geometry is determined. In particular, it is demonstrated that for geometrically similar samples the power spectrum is inversely proportional to the sample volume. It is argued also that the magnitude of fluctuations induced by external electric field is proportional to the field strength squared. A comparison with experimental data on flicker noise measurements in continuous metal films is made.