Stanford directly observes a quantum jump of sound for the first time

Stanford physicists directly watched a mechanical resonator lose a single phonon, the smallest unit of sound energy. The resonator rang for 2 milliseconds, letting a superconducting qubit take hundreds of readings. The result could aid quantum computing error detection and precision sensing.

• Resonator lost exactly one phonon in a quantum jump
• Ringdown time of 2 ms enabled hundreds of measurements
• Qubit distinguished one-phonon and zero-phonon states
• Findings published in Science on September 17, 2026