Collective Dynamics in Circuit Quantum Acoustodynamics with a Macroscopic Resonator

TL;DR

This paper demonstrates collective quantum dynamics in a macroscopic resonator coupled to a superconducting qubit, revealing transitions between static and dynamic regimes and showcasing the system's potential for studying many-body phenomena.

Contribution

It introduces a hybrid quantum acoustodynamic system with an HBAR and a transmon qubit, enabling observation of collective mechanical mode dynamics in a macroscopic device.

Findings

Observation of collective Dicke dynamics in mechanical modes

Transition from static to timed-Dicke regime

Evidence of quantum coherence in collective behavior

Abstract

Collective dynamics in engineered quantum systems offer a unique and versatile platform for exploring how many-body correlations bridge microscopic entanglement and macroscopic behavior. In this work, we report collective Dicke dynamics of acoustic modes in a macroscopic high-overtone bulk acoustic resonator (HBAR). To achieve this, we engineer a hybrid quantum acoustodynamic system comprising an HBAR strongly coupled to a superconducting transmon qubit. The HBAR device is distinctive in the sense that its narrow mode spacing, together with enhanced qubit-mode coupling strength, gives rise to efficient coupling between the transmon and clusters of near-resonant modes. By harnessing the system properties, we observe collective dynamics involving clusters composed by two or three mechanical modes, where their non-resonant spectrum allows for the observation of the transition between the Dicke static regime to dynamically induced timed-Dicke one. The coherent collective behavior of the system is supported by time-domain measurements of the qubit's purity, indicating the quantum nature of the collective dynamics. Overall, our work establishes HBAR-based hybrid quantum system as a promising platform for exploring many-body collective dynamics in macroscopic mechanical systems.