Simple theory of current fluctuations and noise in bridge-mediated nano-junctions.

We develop a simplified, model theory of noise caused by highly damped oscillating conformational fluctuations of a chain molecule mediating a nano-junction. Considering the most 'primitive' approximation of direct tunneling of electrons and barrier coupling with collective coordinates that describe internal conformations of the chain molecule, we derive approximate analytical formulas for the temporary current correlation function, noise power, and Fano factor. We analyze the role of different cumulative parameters of the model that affect the noise, as well as the effect of the temperature and of the number of groups in the chain. We present this analysis in expectation of experiments on this type of noise and in an attempt to trigger such experiments.