Caltech uses sound to store quantum data 30 times longer than qubits

Caltech researchers have developed a novel quantum memory technique that converts quantum electrical signals from superconducting qubits into acoustic vibrations using a chip-scale mechanical oscillator, akin to a microscopic tuning fork. This hybrid approach leverages phonons—quantized sound waves vibrating at gigahertz frequencies—to store quantum information. Because these mechanical vibrations lose energy more slowly and are less prone to interference than electrical signals, the system achieves quantum state lifetimes up to 30 times longer than conventional superconducting qubits. This advancement addresses a key limitation of superconducting qubits, which excel at processing quantum information but suffer from short coherence times that restrict data storage. The team fabricated a nanoscale mechanical oscillator integrated with a superconducting qubit on a chip, enabling the storage and retrieval of quantum states as mechanical vibrations at extremely low temperatures. The slower propagation of acoustic waves allows for compact device design and reduces energy loss by preventing radiation into free space. These properties suggest the potential for scalable quantum memory solutions by integrating many such oscillators