Researchers Observe First Real-Time Quantum Jump in Sound

Insider Brief

• Stanford researchers directly observed individual phonons, or quantum units of sound, making discrete energy jumps in a mechanical resonator in real time.
• The team paired a long-lived microscopic resonator with a superconducting qubit that repeatedly measured whether its vibrational energy was present or had dropped from one quantum level to another.
• The result could support sound-based quantum computing error correction and highly sensitive sensing applications, including efforts to identify proteins within cells.
• Image: This mechanical resonator, depicted in an illustration (left) and in an image taken by a scanning electron microscope (right), allowed researchers to detect quantum jumps of sound. (Erik Szakiel).

PRESS RELEASE — A Stanford team has documented the first direct observation of quantum jumps of sound in a mechanical resonator, completing an arc of scientific exploration that started over a hundred years ago.

Quantum jumps—sudden transitions from one energy state to another—have been theorized since the early 1900s. Scientists first demonstrated these jumps in trapped ions in 1986 and later in photons, the fundamental particles of light, in 2007. Observing quantum jumps of sound had remained elusive, but a team led by Stanford physicist Amir Safavi-Naeini has recorded these phenomena, publishing the findings in the journal Science.