Dark Exciton Giant Rabi Oscillations with no External Magnetic Field

TL;DR

This paper demonstrates giant Rabi oscillations between vacuum and dark exciton states in a quantum dot-cavity system, enabling phonon bundle emission without external magnetic fields, advancing quantum phononics and multi-phonon physics.

Contribution

It introduces a model with dark excitons in a quantum dot coupled to an acoustic cavity, enabling multi-phonon Rabi oscillations without external magnetic fields, which was not previously achieved.

Findings

Giant Rabi oscillations between vacuum and dark exciton states.

Creation of dark state excitations without external magnetic fields.

System acts as a phonon gun emitting N-phonon bundles.

Abstract

Multi-phonon physics is an emerging field that serves as a test bed for fundamental quantum physics and several applications in metrology, on-chip communication, among others. Quantum acoustic cavities or resonators are devices that are being used to study multi-phonon phenomena both theoretically and experimentally. In particular, we study a system consisting of a semiconductor quantum dot pumped by a driving laser, and coupled to an acoustic cavity. This kind of systems has proven to yield interesting multi-phonon phenomena, but the description of the quantum dot has been limited to a two-level system. This limitation restrains the complexity that a true semiconductor quantum dot can offer. Instead, in this work we consider a model where the quantum dot can have both bright and dark excitons, the latter being particularly useful due to their lower decoherence rates, because they do not present spontaneous photon emission. In this setup, we demonstrate that by fine-tuning the driving laser frequency, one is able to realise giant Rabi oscillations between the vacuum state and a dark exciton state with $N$-phonon bundles. From this, we highlight two outstanding features: first, we are able to create dark states excitations in the quantum dot without the usual external magnetic field needed to do so; and second, in a dissipative scenario where the acoustic cavity and the quantum dot suffer from losses, the system acts as a phonon gun able to emit $N$-phonon bundles.