ETH Zurich chip uses mechanical vibrations as quantum working memory, Science study shows

Researchers at ETH Zurich led by quantum physicist Yiwen Chu have demonstrated a quantum architecture that stores information in mechanical vibrations on a fingernail-scale chip, according to SciTechDaily coverage of a study published in Science. The experimental chip measures about 7.5 millimeters by 2.5 millimeters by 1 millimeter. A superconducting qubit acts as processor and control unit while microscopic mechanical resonators hold quantum information as phonons, vibrational energy packets. The design separates calculation from memory in a way that resembles the CPU and RAM split in classical computers, rather than integrating both functions in the same hardware. Chu said the interaction between the quantum processor and quantum memory is a foundation for making quantum computers a powerful and reliable way to run computations that conventional machines cannot. Mechanical resonators are compact, support many separate vibrational modes as memory locations, and can preserve quantum states for relatively long periods, while superconducting qubits provide fast operations and nonlinearity for quantum logic. The team implemented the quantum Fourier transform and a quantum period-finding algorithm as proof-of-principle programmable procedures. Co-author Igor Kladaric, a doctoral student in Chu's team, said the quantum Fourier transform is a fundamental procedure required for many quantum algorithms and that period finding demonstrated how it can be used. The work is a laboratory demonstration, not a commercial computer; scaling memory, processing power, error rates, and control remain open challenges. The paper, Mechanical resonator-based quantum computing, lists Yu Yang, Igor Kladaric, and colleagues with Yiwen Chu, with DOI 10.1126/science.aef4139.