A team at Stanford University, led by physicist Amir Safavi-Naeini, has recorded the first real-time quantum jumps of sound — individual phonons abruptly vanishing from one energy state and reappearing in another. The findings, published in Science, mark a milestone in quantum physics research stretching back more than a century.
The experiment centred on a microscopic mechanical resonator built using chip fabrication techniques. Roughly the size of a tiny tuning fork, the device can vibrate for two milliseconds — an unusually long “ringdown time” that allowed researchers to collect hundreds of repeated measurements and pinpoint the exact moment a phonon jumped from energy state 1 to 0. Co-first authors Takuma Makihara and Erik Szakiel solved a long-standing challenge in quantum engineering by coupling the resonator to a superconducting qubit, enabling measurement without destroying the delicate quantum state.
The implications extend across multiple frontiers. In quantum computing, detecting quantum jumps in sound could provide a new tool for error correction, since jumps often signal that an error has occurred. The team is already collaborating with Caltech physicist Michael Roukes to explore whether the system could detect and identify individual proteins inside cells — potentially creating ultra-sensitive biological sensors.
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