Scientists claim sound can be used to transfer quantum data between atoms

Tiny mechanical vibrations can be used to transfer quantum information, claim scientists

A team of researchers claim to have found a new way of coupling individual atoms, precisely controlling them to enable new technological breakthroughs, such as new types of sensors and secure data transmission methods.

The scientists from the Technical University of Vienna (TU Wien) and Harvard University, joined forces and proposed using tiny mechanical vibrations to couple the atoms with each other by 'phonons', referring to the smallest quantum mechanical units of vibrations or sound waves.

"We are testing tiny diamonds with built-in silicon atoms - these quantum systems are particularly promising," said Professor Peter Rabl from TU Wien.

"Normally, diamonds are made exclusively of carbon, but adding silicon atoms in certain places creates defects in the crystal lattice where quantum information can be stored."

These microscopic flaws in the crystal lattice can be used like a tiny switch that can be switched between a state of higher energy and a state of lower energy using microwaves.

With a team from Harvard University, Peter Rabl's research group developed a new idea to achieve the targeted coupling of these quantum memories within the diamond, by building them one by one into a tiny diamond rod measuring only a few micrometres in length, like individual pearls on a necklace.

Just like a tuning fork, this rod can then be made to vibrate, and through these tiny vibrations the silicon atoms can form a quantum-mechanical link to each other.

"Light is made from photons, the quantum of light. In the same way, mechanical vibrations or sound waves can also be described in a quantum-mechanical manner," explained Rabl.

"As the research team has now been able to show using simulation calculations, any number of these quantum memories can be linked together in the diamond rod thanks to these phonons.

"The individual silicon atoms are ‘switched on and off' using microwaves. During this process, they emit or absorb phonons. This creates a quantum entanglement of different silicon defects, thus allowing quantum information to be transferred."

The main advantage of this new technology lies in its scalability, the researchers claim.

There are many ideas for quantum systems that could, in theory, be used for technological applications," Rabl added. "The biggest problem is that it is very difficult to connect enough of them to be able to carry out complicated computing operations.

"The new strategy of using phonons for this purpose could pave the way to a scalable quantum technology."