Time ordering and counting statistics
arXiv:0907.3848 · doi:10.1007/s10955-009-9885-z
Abstract
The basic quantum mechanical relation between fluctuations of transported charge and current correlators is discussed. It is found that, as a rule, the correlators are to be time-ordered in an unusual way. Instances where the difference with the conventional ordering matters are illustrated by means of a simple scattering model. We apply the results to resolve a discrepancy concerning the third cumulant of charge transport across a quantum point contact.
19 pages, 1 figure; inconsequential mistake and typos corrected