Phonitons as a sound-based analogue of cavity quantum electrodynamics

TL;DR

This paper proposes phonitons, sound-based analogues of cavity quantum electrodynamics, demonstrating strong phonon-matter coupling in silicon with potential for quantum devices.

Contribution

It introduces the concept of phonitons, showing their realization in strained silicon and the feasibility of high-Q phonon cavities for quantum applications.

Findings

Strong phonon-matter coupling achieved in silicon

High-Q micropillar Bragg reflector cavities with Q=10^5-10^6

Potential for single and many-body quantum devices

Abstract

A quantum mechanical superposition of a long-lived, localized phonon and a matter excitation is described. We identify a realization in strained silicon: a low-lying donor transition (P or Li) driven solely by acoustic phonons at wavelengths where high-Q phonon cavities can be built. This phonon-matter resonance is shown to enter the strongly coupled regime where the "vacuum" Rabi frequency exceeds the spontaneous phonon emission into non-cavity modes, phonon leakage from the cavity, and phonon anharmonicity and scattering. We introduce a micropillar distributed Bragg reflector Si/Ge cavity, where Q=10^5-10^6 and mode volumes V<=25*lambda^3 are reachable. These results indicate that single or many-body devices based on these systems are experimentally realizable.