Shot Noise and Full Counting Statistics from Non-equilibrium Plasmons in Luttinger-Liquid Junctions

TL;DR

This paper investigates how non-equilibrium plasmonic excitations in a Luttinger-liquid junction system significantly enhance shot noise beyond the Poisson limit, revealing new transport phenomena due to non-equilibrium effects.

Contribution

It provides a theoretical analysis of shot noise in a double quantum wire junction with non-equilibrium plasmons, highlighting their impact on noise enhancement and transport processes.

Findings

Non-equilibrium plasmons greatly increase shot noise beyond Poisson limit.

Multiple current-carrying processes emerge due to non-equilibrium plasmons.

Fast plasmon relaxation suppresses the noise enhancement.

Abstract

We consider a quantum wire double junction system with each wire segment described by a spinless Luttinger model, and study theoretically shot noise in this system in the sequential tunneling regime. We find that the non-equilibrium plasmonic excitations in the central wire segment give rise to qualitatively different behavior compared to the case with equilibrium plasmons. In particular, shot noise is greatly enhanced by them, and exceeds the Poisson limit. We show that the enhancement can be explained by the emergence of several current-carrying processes, and that the effect disappears if the channels effectively collapse to one due to, {\em e.g.}, fast plasmon relaxation processes.