Frequency dispersion of photon-assisted shot noise in mesoscopic conductors

TL;DR

This paper investigates how the low-frequency current noise in AC biased mesoscopic conductors depends on electron diffusion time rather than electric response time, revealing new insights into noise behavior.

Contribution

It demonstrates that noise frequency dispersion is governed by electron diffusion time, contrasting with admittance behavior dominated by RC time, and provides experimentally verifiable predictions.

Findings

Frequency dispersion is driven by electron diffusion time.

Noise fluctuations originate from Fermi distribution variations.

Predictions are testable with current experimental setups.

Abstract

We calculate the low-frequency current noise for AC biased mesoscopic chaotic cavities and diffusive wires. Contrary to what happens for the admittance, the frequency dispersion is not dominated by the electric response time (the "RC" time of the circuit), but by the time that electrons need to diffuse through the structure (dwell time or diffusion time). Frequency dispersion of noise stems from fluctuations of the Fermi distribution function that preserve charge neutrality. Our predictions can be verified with present experimental technology.