Noise Intensity-Intensity Correlations and the Fourth Cumulant of Current Fluctuations

TL;DR

This paper investigates how noise intensity correlations in a tunnel junction under ac excitation relate to the fourth cumulant of current fluctuations, revealing photon bunching phenomena dependent on bias and frequency relations.

Contribution

It demonstrates that noise intensity correlations are proportional to the fourth cumulant of current fluctuations, linking optical-like correlations to electronic noise statistics.

Findings

Positive noise intensity correlations (photon bunching) observed under specific frequency and bias conditions.

Correlations are proportional to the fourth cumulant of current fluctuations.

Dependence of correlations on excitation frequency and dc bias established.

Abstract

We report measurements of the correlation between intensities of noise at different frequencies on a tunnel junction under ac excitation, which corresponds to two-mode intensity correlations in optics. We observe positive correlation, \emph{i.e.} photon bunching, which exist only for certain relations between the excitation frequency and the two detection frequencies, depending on the dc bias of the sample. We demonstrate that these correlations are proportional to the fourth cumulant of current fluctuations.