Long-Range Coulomb Interaction and the Crossover between Quantum and Shot Noise in Diffusive Conductors

TL;DR

This paper investigates how long-range Coulomb interactions influence frequency-dependent noise in diffusive conductors, revealing a crossover from quantum to shot noise at low frequencies and establishing conditions for equivalence between semiclassical and quantum approaches.

Contribution

It provides a detailed analysis of the crossover between quantum and shot noise considering Coulomb interactions, highlighting frequency regimes where semiclassical and quantum methods align.

Findings

Crossover between quantum and shot noise occurs at low frequencies for long contacts.

Long-range Coulomb interactions significantly affect noise characteristics.

Semiclassical and quantum-coherent approaches are mathematically equivalent under certain conditions.

Abstract

Frequency-dependent nonequilibrium noise in quantum-coherent diffusive conductors is calculated with account taken of long-range Coulomb interaction. For long and narrow contacts with strong external screening the crossover between quantum and shot noise takes place at frequencies much smaller than the voltage drop across the contact. We also show that under certain frequency limitations, the semiclassical and quantum-coherent approaches to shot noise are mathematically equivalent.