Neutral mode heat transport and fractional quantum Hall shot noise

TL;DR

This paper investigates how neutral modes in fractional quantum Hall states influence heat transport and shot noise, revealing their counter-propagating nature through excess noise measurements caused by temperature differences.

Contribution

It introduces a method to detect counter-propagating neutral modes via excess noise induced by heat transport in fractional quantum Hall systems.

Findings

Excess noise correlates with neutral mode heat transport.

Neutral modes cause measurable temperature differences between edges.

The dependence of noise on bias and temperature difference is characterized.

Abstract

We study nonequilibrium edge state transport in the fractional quantum Hall regime for states with one or several counter-propagating neutral modes. We consider a setup in which the neutral modes are heated by a hot spot, and where heat transported by the neutral modes causes a temperature difference between the upper and lower edges in a Hall bar. This temperature difference is probed by the excess noise it causes for scattering across a quantum point contact. We find that the excess noise in the quantum point contact provides evidence for counter-propagating neutral modes, and we calculate its dependence on both the temperature difference between the edges and on source drain bias.