Quantum Leap: Scientists Use Sound Waves to Shape the Future of the Internet

quantum internet sound waves

Researchers have innovated fresh approaches for connecting light with surface-traveling sound waves.

At the University of Rochester, a team has leveraged surface acoustic waves to address a significant obstacle in the pursuit of a quantum internet.

In a recent publication in Nature Communications, experts from Rochester’s Institute of Optics and Department of Physics and Astronomy unveil a method for synchronizing particles of light and sound.

This breakthrough could enable the accurate conversion of quantum information—qubits—into optical signals, which can then be transmitted across vast distances.

What are Surface Acoustic Waves?

Surface acoustic waves are oscillations that glide along the surface of materials, akin to the movement of waves across the ocean or seismic tremors during an earthquake.

These waves have found diverse applications, notably in the electronic components of smartphones where surface acoustic wave filters are employed.

Their ability to create highly precise cavities is invaluable for applications requiring exact timing, such as navigation. Recently, these waves have been harnessed for quantum technologies as well.

“In the past decade, surface acoustic waves have proven to be a valuable asset for quantum applications due to their effective coupling with various systems,” notes William Renninger, an associate professor specializing in optics and physics.

Conventionally, surface acoustic waves are accessed, manipulated, and regulated through piezoelectric materials, converting electrical signals into acoustic waves and vice versa.

However, this process necessitates the insertion of mechanical fingers into the acoustic cavity, leading to parasitic effects by scattering phonons, which then require correction.

Manipulating Surface Acoustic Waves with Light

Rather than coupling phonons to electric fields, Renninger’s research group explored a less intrusive method by directing light into the cavities, thus removing the need for mechanical intervention.

“We achieved a strong coupling between surface acoustic waves and light,” says Arjun Iyer, a PhD student in optics and the study’s lead author.

“We engineered acoustic cavities—essentially tiny echo chambers—where sound could resonate for extended periods, facilitating stronger interactions.

Remarkably, our method is effective on any material, not just the piezoelectric materials that are traditionally used for electrical control.”

Renninger’s team collaborated with the laboratory of Associate Professor John Nichol from the Physics Department to create the surface acoustic wave devices featured in the study.

These devices not only enable robust quantum coupling but also offer the advantages of straightforward fabrication, compact size, and the capability to manage significant power loads.

Beyond their potential in hybrid quantum computing, the researchers assert that their techniques could be applied in spectroscopy to investigate material properties, function as sensors, and advance the study of condensed matter physics.

Reference

Iyer, A., Kandel, Y. P., Xu, W., Nichol, J. M., & Renninger, W. H. (2024). “Coherent optical coupling to surface acoustic wave devices.” Nature Communications. Published on May 11, 2024.

Credit: University of Rochester illustration / Iyer et al.