Researchers prepared a microgram-scale vibrating acoustic resonator in quantum states of up to seven phonons, using a qubit. The device detected weak signals 7.0 dB more sensitively than any classical probe, and a neural network achieved the same gain with half the bias.
Mechanical probes of force, acceleration, and gravity are capped by a quantum noise limit. This device, far heavier than earlier quantum-enhanced systems, clears that cap — though imperfect state preparation still limits the gain. That opens a lab-scale route to search for dark matter and high-frequency gravitational waves.
✦ Quantum states let a tiny vibrating device hear signals fainter than any classical sensor could.