Researchers have successfully engineered a device that generates controlled bursts of sound-like vibrations at the quantum level, a breakthrough that could revolutionize how we transmit data through water and biological tissue.
The innovation, developed by a team from McGill University and the National Research Council of Canada, produces phonons —quantum particles of sound—using electrical currents in ultra-cold conditions. This technology addresses a critical limitation in modern communication: while light and electricity dominate current networks, they struggle to travel through mediums like oceans or the human body, where sound waves excel.
How the Device Works
The core of this invention lies in manipulating electrons within a two-dimensional crystal layer, just a few atoms thick. When an electrical current is forced through this narrow channel, the electrons accelerate to speeds exceeding the speed of sound within that material.
As these “supersonic” electrons move, they shed energy in the form of phonons. This process creates predictable, controllable bursts of sound vibrations. However, this phenomenon is fragile; it only occurs under extreme cooling. The device must be maintained at temperatures between 10 millikelvin and 3.9 Kelvin —near absolute zero—to ensure electrons move orderly enough for quantum effects to manifest.
“At absolute zero temperatures… no sound is created unless electrons travel collectively at the speed of sound or above,” explained Michael Hilke, Associate Professor of Physics at McGill and co-author of the study. “Our study goes further by pushing the system well beyond that point.”
Why This Matters
Current communication infrastructure relies heavily on electromagnetic waves (light) and electrical currents. These signals degrade rapidly in water and are often blocked or scattered by biological tissues. Sound, however, travels efficiently through these mediums.
By creating a reliable source of quantum sound, scientists are laying the groundwork for phonon lasers —devices that amplify sound waves in the same way optical lasers amplify light. This could lead to:
- Deep-sea communication: High-speed data transmission underwater without relying on cables or acoustic modems that are currently slow and bulky.
- Medical diagnostics: Precise, non-invasive sensing tools that use sound waves to probe biological materials with greater clarity.
- Advanced sensors: Highly sensitive detection systems for industrial and scientific applications.
Challenging Existing Theories
The research also reveals unexpected physics. Traditionally, it was assumed that for such quantum effects to occur, the entire system needed to be cold. However, the McGill team found that even if the host crystal is near absolute zero, the electrons themselves can be “very hot” (high energy) relative to their surroundings. This finding suggests that existing theoretical models need to be reassessed to account for this disparity between the temperature of the material and the energy of the particles moving through it.
Future Directions
While the current prototype requires extreme cooling, researchers are already looking toward practical applications. Future work will explore whether other materials, such as graphene, could allow the device to operate at higher speeds or less extreme temperatures.
“Phonons are hard to generate and harness in a controlled way, so we are exploring new regimes,” said Hilke. “At a broad level, this is about how electrical current and energy moves and is converted inside advanced electronic materials.”
Conclusion
This breakthrough represents a significant step toward mastering sound at the quantum scale. By converting electrical energy into controlled sound vibrations, scientists are unlocking new possibilities for communication and sensing in environments where traditional light-based technologies fail.
