Stimulated Phonon Emission in a Driven Double Quantum Dot

TL;DR

This paper investigates how microwave-driven double quantum dots in GaAs generate phonons, revealing stimulated phonon emission that affects quantum information processing by providing spectroscopic insights into the phononic environment.

Contribution

It demonstrates stimulated phonon emission in a driven double quantum dot, highlighting a microwave Raman-like process and its spectroscopic signatures in a GaAs quantum device.

Findings

Stimulated phonon emission causes population inversion.

Spectroscopic signatures reveal phononic environment.

Microwave analog of Raman effect observed.

Abstract

The compound semiconductor gallium arsenide (GaAs) provides an ultra-clean platform for storing and manipulating quantum information, encoded in the charge or spin states of electrons confined in nanostructures. The absence of inversion symmetry in the zinc-blende crystal structure of GaAs however, results in strong piezoelectric coupling between lattice acoustic phonons and electrons, a potential hindrance for quantum computing architectures that can be charge-sensitive during certain operations. Here we examine phonon generation in a GaAs double dot, configured as a single- or two-electron charge qubit, and driven by the application of microwaves via surface gates. In a process that is a microwave analog of the Raman effect, stimulated phonon emission is shown to produce population inversion of a two-level system and provides spectroscopic signatures of the phononic environment created by the nanoscale device geometry.