Researchers at Stanford have developed a “quantum microphone” which can detect the smallest known units of sound — packets of vibrational energy called phonons. The device could form the basis for even more efficient quantum computers.
Phonons have previously been impossible to measure because traditional microphones are not nearly sensitive enough to pick them up. A microphone works by detecting when a sound wave interacts with a membrane, but the phonons are so small that they can’t be detected individually due to the Heisenberg Uncertainty Principle.
Instead of relying on indirect measurement of sound waves, the scientists built a device which measures the energy of phonons directly using minuscule resonators which act like mirrors for sound. The device can trap the photons and measure the vibrations they cause, with different energy levels corresponding to different numbers of phonons.
The device is described in a paper in Nature, and could be a step towards the creation of a new type of quantum computer. The ability to detect small packets of sound could allow for devices which encode information using sound energy, allowing the storage of massive amounts of data in a smaller space.
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