New research uses sound waves to mimic atomic behavior and advance computing

For every action, there is an equal and opposite reaction. What goes up, must come down. Physical laws like these govern all of the natural world — except for the tiny internal components of today’s microprocessors, which operate according to the unique and complicated rules of quantum physics.

As the microprocessors that power computers, medical equipment, sensors, and more continue to shrink in size, engineers face challenges controlling quantum-scale systems. But in a step forward for the technology, researchers at Virginia Tech have developed an “acoustic atom” — a chip-scale device that traps and controls sound waves in ways that mimic the behavior of real atoms. Long term, these advances could influence technologies connected to quantum artificial intelligence (AI), telecommunication, medical imaging, GPS, and more.

The research was recently published in Physical Review Letters by Linbo Shao, assistant professor in Virginia Tech's Bradley Department of Electrical and Computer Engineering, along with colleagues at the university's Center for Power Electronic Systems, Department of Physics, and Center for Quantum Information Science and Engineering and the Oak Ridge National Laboratory. 

The quantum realm creates multiple challenges for quantum systems, such as scalability, the unintentional interaction of signals, and the limited lifetime of fragile quantum information. Vibration, heat, material defects, and electromagnetic noise also have a great impact at the quantum scale.

Acoustic waves offer a compact and sustainable way to process and route signals, opening new possibilities for quantum and microwave technologies, according to the study.

“In nature, an atom has distinct energy levels that electrons can jump between,” said Shao. “Our acoustic atom is a device with distinct energy levels for acoustic waves. Using electrical fields, we can drive transitions between these acoustic energy levels, mimicking real atoms.”

New pathways for the future

By recreating the controllable behaviors found in atomic systems, researchers can explore new pathways for future signal-processing and quantum systems. Unlike electromagnetic waves, acoustic waves can be confined to a microscopic footprint and hold information or energy for far longer. 

Acoustic atoms, according to the research, could eventually contribute to:

• Smaller microwave communication components
• Improved signal routing and filtering
• Analog computing systems
• Interfaces for quantum hardware
• Highly sensitive sensing technology

“Ultimately, we hope this platform provides a new, highly compact way to process signals and perform analog acoustic computing directly on a chip,” Shao said. “Right now, we’re using classical, coherent microwave sources to drive the acoustic waves. There’s a long way to get this down to the single phonon level, but we’re optimistic that all those will happen soon by collaborating with Virginia Tech Center for Quantum Information Science and Engineering and Center for Power Electronic Systems faculty.”

Collaborators include:

• Jun Ji, postdoctoral researcher, Bradley Department of Electrical and Computer Engineering
• Joseph G. Thomas, graduate student, Bradley Department of Electrical and Computer Engineering
• Zichen Xi, graduate student, Bradley Department of Electrical and Computer Engineering
• Liyang Jin, graduate student, Bradley Department of Electrical and Computer Engineering
• Liyan Zhu, assistant professor, Bradley Department of Electrical and Computer Engineering
• Yizheng Zhu, associate professor, Bradley Department of Electrical and Computer Engineering
• Arya G. Pour, graduate student, Department of Physics
• Daryll P. Briggs, lead cleanroom engineer, Oak Ridge National Laboratory
• Ivan I. Kravchenko, senior research and development staff member, Oak Ridge National Laboratory

Original study: DOI 10.1103/hv6r-2ptj