Scientists Catch Sound Making a Quantum Jump With a Microscopic Tuning Fork

Scientists from Stanford University have successfully observed a quantum jump in phonons, the units of sound, for the first time. Quantum jumps, the sudden transition of a quantum system from one energy state to another, had been recorded in ions and photons previously, but phonon jumps remained elusive. The research, published in the journal Science, marks a significant step forward in understanding the phenomenon.

Quantum jumps have been theorized since the 1910s, when physicist Niels Bohr proposed his model of the atom. However, observing these jumps has proven challenging due to their short timescales and seemingly random nature. The first direct observation of a quantum jump occurred in 1986, involving trapped ions, followed by a similar observation in photons in 2007.

The Stanford team overcame obstacles in detecting phonon jumps by building a mechanical resonator, akin to a microscopic tuning fork that can vibrate for up to two milliseconds. By coupling the resonator with an electrical circuit known as a superconducting qubit, the researchers were able to measure the moment when the number of phonons transitions from one to zero, unveiling the elusive quantum jumps in sound.