Statistical electron excitation in a double quantum dot induced by two independent quantum point contacts

TL;DR

This study experimentally examines how current flow through quantum point contacts influences a nearby double quantum dot, revealing that acoustic phonons, not shot noise, dominate the interaction mechanism.

Contribution

It demonstrates that the double quantum dot's behavior is primarily affected by a bosonic bath of acoustic phonons rather than shot noise from quantum point contacts.

Findings

Current flow affects the quantum dot via a bosonic bath.

Acoustic phonons are identified as the main interaction mechanism.

Shot noise coupling is experimentally excluded.

Abstract

We investigate experimentally the influence of current flow through two independent quantum point contacts to a nearby double quantum dot realized in a GaAs-AlGaAs heterostructure. The observed current through the double quantum dot can be explained in terms of coupling to a bosonic bath. The temperature of the bath depends on the power generated by the current flow through the quantum point contact. We identify the dominant absorption and emission mechanisms in a double quantum dot as an interaction with acoustic phonons. The experiment excludes coupling of a double quantum dot to shot noise generated by quantum point contact as the dominant mechanism.