Detecting THz current fluctuations in a quantum point contact using a nanowire quantum dot

TL;DR

This paper demonstrates the use of a nanowire quantum dot to detect high-frequency current fluctuations in a quantum point contact, revealing photon-mediated interactions and enabling infrared radiation detection.

Contribution

It introduces a novel method for probing high-frequency fluctuations using a nanowire quantum dot across different material systems.

Findings

Detection of real-time charge transitions driven by current fluctuations

Evidence of photon-mediated interactions between quantum systems

Capability to detect infrared radiation using nanowire quantum dots

Abstract

We use a nanowire quantum dot to probe high-frequency current fluctuations in a nearby quantum point contact. The fluctuations drive charge transitions in the quantum dot, which are measured in real-time with single-electron detection techniques. The quantum point contact (GaAs) and the quantum dot (InAs) are fabricated in different material systems, which indicates that the interactions are mediated by photons rather than phonons. The large energy scales of the nanowire quantum dot allow radiation detection in the long-wavelength infrared regime.