Researchers break ground in quantum internet with surface acoustic wave

Scientists have achieved a breakthrough in the quest for a quantum internet using surface acoustic waves. In a new study published in Nature Communications, researchers from the University of Rochester's Institute of Optics and the Department of Physics and Astronomy detail a novel technique that pairs light and sound particles to convert information stored in quantum systems - known as qubits - into optical fields that can be transmitted over long distances.

Surface acoustic waves are vibrations that travel along the surface of materials, akin to ripples on a pond or tremors during an earthquake. These waves have a variety of applications - for instance, they are used in many of the electrical components of our phones. Now they are being used in quantum applications as well.

“In the last 10 years, surface acoustic waves have emerged as a good resource for quantum applications because the phonon, or individual particle of sound, couples very well to different systems,” says William Renninger, associate professor of optics and physics.

Traditionally, piezoelectric materials are used to access, manipulate and control surface acoustic waves to convert electricity into acoustic waves and vice versa. However, this method involves inserting mechanical fingers into the acoustic cavity, causing parasitic effects by scattering phonons, which need to be compensated for.

Renninger's team, however, took a less invasive approach - using light itself to manipulate the surface acoustic waves, shining light on the cavities and thus eliminating mechanical contact.

“We were able to strongly couple surface acoustic waves with light,” says Arjun Iyer, an optics PhD student and first author of the paper.

This novel yet powerful technique not only produces strong quantum coupling but also boasts simple fabrication, small size, and the capacity to handle large amounts of power.

This groundbreaking technique extends beyond the realm of quantum communication. It can be utilized in spectroscopy to explore material properties, as sensors, and to study condensed matter physics.