Shot noise in mesoscopic systems

TL;DR

This review discusses shot noise in mesoscopic conductors, highlighting how quantum correlations reduce noise below Poisson levels, with universal suppression factors in various systems, and reviews experimental observations and future phenomena of interest.

Contribution

It provides a comprehensive overview of shot noise suppression mechanisms and universal values in mesoscopic systems, including recent experimental findings and open questions.

Findings

Shot noise can be suppressed below Poisson levels due to electron correlations.

Universal suppression factors are identified for different mesoscopic structures.

Experimental observation of sub-Poissonian shot noise confirms theoretical predictions.

Abstract

This is a review of shot noise, the time-dependent fluctuations in the electrical current due to the discreteness of the electron charge, in small conductors. The shot-noise power can be smaller than that of a Poisson process as a result of correlations in the electron transmission imposed by the Pauli principle. This suppression takes on simple universal values in a symmetric double-barrier junction (suppression factor 1/2), a disordered metal (factor 1/3), and a chaotic cavity (factor 1/4). Loss of phase coherence has no effect on this shot-noise suppression, while thermalization of the electrons due to electron-electron scattering increases the shot noise slightly. Sub-Poissonian shot noise has been observed experimentally. So far unobserved phenomena involve the interplay of shot noise with the Aharonov-Bohm effect, Andreev reflection, and the fractional quantum Hall effect.