Transmission and reflection of charge density waves in a quantum Hall edge controlled by a metal gate

TL;DR

This paper investigates how charge density waves in quantum Hall edge channels are transmitted and reflected under gate control, revealing threshold voltages that switch wave direction independently of current flow cessation.

Contribution

It demonstrates experimental control and analysis of charge density wave transmission and reflection in quantum Hall edges using gate voltages, highlighting non-trivial threshold behaviors.

Findings

Charge density wave waveform is proportional to the derivative of applied voltage.

Transmission and reflection are controllable via gate voltages.

Threshold voltages for wave direction switching differ from current stopping points.

Abstract

Quantum energy teleportation (QET) is a proposed protocol related to the quantum vacuum. The edge channels in a quantum Hall system is well suited for the experimental verification of QET. For this purpose, we examine a charge density wave excited and detected by capacitively coupled front gate electrodes. We observe the waveform of the charge density wave, which is proportional to the time derivative of the applied square voltage wave. Further, we study the transmission and reflection behaviors of the charge density wave by applying a voltage to another front gate electrode to control the path of the edge state. We show that the threshold voltages where the dominant direction is switched in either transmission or reflection for dense and sparse waves are different from the threshold voltage where the current stops flowing in an equilibrium state.