A phononic crystal coupled to a transmission line via an artificial atom

TL;DR

This paper explores the interaction between a phononic crystal and an artificial atom in the quantum regime, demonstrating coupling of acoustic and electromagnetic degrees of freedom and analyzing the system's modes and spectra.

Contribution

It introduces a novel system coupling a phononic crystal with an artificial atom, enabling quantum acoustic effects in a compact, integrated setup.

Findings

Identification of quasinormal modes of the phononic crystal

Simulation results consistent with experimental mode measurements

Visualization of acoustic modes via electromagnetic scattering spectrum

Abstract

We study a phononic crystal interacting with an artificial atom { a superconducting quantum system { in the quantum regime. The phononic crystal is made of a long lattice of narrow metallic stripes on a quatz surface. The artificial atom in turn interacts with a transmission line therefore two degrees of freedom of different nature, acoustic and electromagnetic, are coupled with a single quantum object. A scattering spectrum of propagating electromagnetic waves on the artificial atom visualizes acoustic modes of the phononic crystal. We simulate the system and found quasinormal modes of our phononic crystal and their properties. The calculations are consistent with the experimentally found modes, which are fitted to the dispersion branches of the phononic crystal near the first Brillouin zone edge. Our geometry allows to realize effects of quantum acoustics on a simple and compact phononic crystal.