A Shivering Disk Cooled to Quantum Stillness ⚡ экспресс
Scientists have cooled a microscopic disk to a state where its vibrations almost disappeared—leaving less than one quantum of vibration (phonon). Imagine a tuning fork frozen in absolute silence: such cooling opens the door to the quantum world of macroscopic objects. Will we one day be able to 'hear' silence at the quantum level?
Cooled nearly to absolute zero with liquid helium, the semiconductor disk reached such a low level of entropy that its thermal trembling became less than one phonon — a quantum of sound. An ordinary guitar string plucked produces billions of phonons; here, it's less than one, like a string frozen in quantum uncertainty: both moving and not.
To measure this microscopic motion, researchers brought a thin optical fiber close to the disk. Light grazing the disk scattered and revealed phonons. This technique — Brillouin sideband spectroscopy — showed an average of 0.66 phonons in the disk. However, the measuring light itself slightly heated the disk, hindering complete cooling — like a bow that adds tremble instead of calming the string.
Such control over a large object blurs the line between our world and the quantum one. Quantum-cooled systems will become the heart of sensors that can hear gravitational waves or single molecules.
🎯 The disk cooling uses a mixture of liquid helium-3 and helium-4: separating the mixture extracts heat — much like evaporating sweat cools your skin, but far more efficient.