The Future of Sound in Quantum Computing %

In the context of wave particle duality just like light has “particles” called photons, sound also has particles called phonons. These particles, in-fact, are quasiparticles – a phenomenon that occurs when a microscopically complicated system behaves as if it were a particle.

A quantum computer can deliver technology’s long-promised ability to help scientists do things like develop miraculous new materials, encrypt data with near-perfect security and accurately predict how the Earth’s climate will change. A qubit (quantum bit) – the basic unit of information in a quantum computer – can represent a 0 and a 1 at the same time unlike classic computers today, which can only represent a 0 or a 1. This phenomenon is known in physics as superposition and is the reason that quantum computers can perform vast numbers of calculations at once, massively increasing computing speed and capacity.

Prototype quantum computers use photons to store information in order to achieve this unparalleled processing power. Using sound instead may have advantages, though it would require manipulating phonons on very fine scales.

Until the recent past, scientists did not possess this ability since detecting the phonon destroyed it. In a new study, scientists at JILA, a joint institute of the National Institute of Standards and Technology and the University of Colorado Boulder, created a circuit in which the phonons would speed up current in the circuit without itself being destroyed. This was done by the help of a special material that created an electric field in response to vibrations caused by the phonons. Now experimenters could detect the changes in current caused by phonons.

The slower speed of sound, as compared to light, also possesses an advantage: it helps researchers to coordinate circuit-phonon interactions more precisely. Consequently, a phonon quantum computer could be even more compact and efficient than a quantum computer which uses photons, as phonons are easier to manipulate.

Applications for sound in quantum computing are far off, as scientists still need to find a way to keep phonons alive much longer than 600 nanoseconds (the time they can currently be kept alive for). Eventually, though, the research could open new paths forward in quantum computing.