High quality quasinormal modes of phononic crystals for quantum acoustodynamics

TL;DR

This paper proposes a phononic crystal structure with Bragg mirrors to significantly enhance the Q-factor, reaching up to 60,000 experimentally, thereby advancing quantum acoustodynamics research.

Contribution

It introduces a novel phononic crystal design with Bragg mirrors that greatly improves the Q-factor compared to traditional structures.

Findings

Simulations predict Q-factors up to 100,000.

Experimental results show a Q-factor of 60,000.

Q-factor is 60 times higher than similar-sized acoustic crystals.

Abstract

Phononic crystals are a promising platform for the study of quantum acoustodynamics. In a recent experiment, the interaction of a superconducting quantum bit with modes of a phononic crystal has been demonstrated. The field of these modes is localized in a compact area, providing high values of the coupling constant with the qubit. However, the Q-factor of phononic crystal modes is strongly limited (1050) due to a phonon emission from the crystal ends. For further use of phononic crystals in research in the field of quantum acoustodynamics, it is desirable to overcome this limitation in the quality factor. In this work, we have proposed a structure consisting of a phononic crystal placed between the Bragg mirrors. Our simulations predict that the Q-factor in such a structure can reach (100000). We demonstrate experimental results in which this structure has a Q-factor (60,000), which is 60 times higher than that of an acoustic crystal of the same size.