Interfacing planar superconducting qubits with high overtone bulk acoustic phonons

TL;DR

This paper demonstrates coupling of high overtone bulk acoustic phonons with a superconducting transmon qubit in a planar circuit, advancing quantum control of mechanical systems for hybrid quantum technologies.

Contribution

It presents the first integration of high overtone bulk acoustic resonators with superconducting qubits in a planar architecture at the quantum level.

Findings

Bulk acoustic phonons interact with the qubit at the quantum level.

The system operates at dilution refrigeration temperatures.

Strong coupling between phonons and qubits is achieved.

Abstract

Mechanical resonators are a promising way for interfacing qubits in order to realize hybrid quantum systems that offer great possibilities for applications. Mechanical systems can have very long energy lifetimes, and they can be further interfaced to other systems. Moreover, integration of mechanical oscillator with qubits creates a potential platform for exploration of quantum physics in macroscopic mechanical degrees of freedom. Utilization of high overtone bulk acoustic resonators coupled to superconducting qubits is an intriguing platform towards these goals. These resonators exhibit a combination of high frequency and high quality factors. They can reach their quantum ground state at dilution refrigeration temperatures and they can be strongly coupled to superconducting qubits via their piezoelectric effect. In this report, we demonstrate our system where bulk acoustic phonons of a high overtone resonator are coupled to a transmon qubit in a planar circuit architecture. We show that the bulk acoustic phonons are interacting with the qubit in the simple design architecture at the quantum level, representing further progress towards quantum control of mechanical motion.