Quantum Computing with Sound Waves express
Inside a tiny crystal, sound is trapped like light in a mirrored room. It bounces off the walls and forms standing waves — a multitude of harmonic oscillations, each with its own frequency. Physicists have learned to use these oscillations as qubits — the basic units of quantum information.
The key element is a superconducting qubit that acts as the conductor of an orchestra of acoustic modes. It controls their states by performing single-qubit gates and controlled-phase gates. Such a set is universal: any quantum algorithm can be assembled from it. The experiment confirmed this by running the quantum Fourier transform and a period-finding algorithm.
The result is an important step toward quantum technologies where sound waves serve as memory and computational elements. Such hybrid systems combine the strengths of different platforms: fast superconducting circuits and long-lived mechanical modes.
Original abstract
as written by the authors arXiv:2601.07825
Hybrid quantum systems combine the unique advantages of different physical platforms with the goal of realizing more powerful and practical quantum information processing devices. Mechanical systems, such as bulk acoustic wave resonators, feature a large number of highly coherent harmonic modes in a compact footprint, which complements the strong nonlinearities and fast operation times of superconducting quantum circuits. Here, we demonstrate an architecture for mechanical resonator-based quantum computing, in which a superconducting qubit is used to perform quantum gates on a collection of mechanical modes. We show the implementation of a universal gate set, composed of single-qubit gates and controlled arbitrary-phase gates, and showcase their use in the quantum Fourier transform and quantum period finding algorithms. These results pave the way toward using mechanical systems to build crucial components for future quantum technologies, such as quantum random-access memories.
Mechanical resonators can store quantum information longer than superconducting qubits, thanks to the high coherence of acoustic oscillations.
The idea of using sound waves for computation echoes the science-fiction concept of acoustic computers that process information through vibrations of a crystal lattice.