An apparatus that includes a quantum object called a qubit (gold) and a device (purple) to translate the sound into electrical signals. can detect a single ‘particle’ of sound. Credit: L. R. Sletten et al./Phys. Rev. X
A quantum object called a qubit helps scientists to pick out a single unit of sound.

For the first time, scientists can count individual phonons — the smallest units of sound — without destroying them.

According to quantum mechanics, the vibrations that make up a sound wave are composed of discrete units of vibration called phonons. Scientists have not yet developed methods to detect an individual phonon without destroying it.

To pick out a single phonon, Lucas Sletten and his colleagues at JILA, a joint institute of the National Institute of Standards and Technology and the University of Colorado Boulder, relied on quantum objects called qubits. A qubit registers the presence of phonons through a shift in its energy level.

The team penned phonons in an enclosure and connected them to a device that converted phonons into two sets of electrical signals. The interaction between these signals enhanced the qubit’s energy shifts and enabled the team to detect a single phonon.

The technique takes advantage of sound’s slowness relative to light; the equivalent set-up for photons would require a much larger device.

This method could allow researchers to use phonons in advanced quantum-information processing systems, the authors write.

Source: Detecting the softest sounds in the Universe

Random sensory quotes

The author O. Henry taught me about the value of the unexpected. He once wrote about the noise of flowers and the smell of birds – the birds were chickens and the flowers dried sunflowers rattling against a wall.

— Chuck Jones